Lubricating fluid for internal combustion engines fueled with alternative combustion fuels having high auto-ignition temperatures

Abstract

A lubricating oil composition configured for lubricating an internal combustion engine fueled with an alternative fuel having an auto-ignition temperature greater than about 700K. The lubricating oil composition includes select amounts of a viscosity modifier olefin copolymer and / or a select detergent system to mitigate stochastic pre-ignition in internal combustion engines when fueled with the alternative fuels.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application is a continuation-in-part of U.S. patent application Ser. No. 18 / 931,962, filed on Oct. 30, 2024, which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure relates to lubricating fluids for internal combustion engines fueled with alternative combustion fuels having high auto-ignition temperatures, as well as methods of lubricating an internal combustion engine using the lubricating fluids when fueled with such alternative combustion fuels.BACKGROUND

[0003] Automotive and powertrain manufacturers are investigating alternative combustion fuels as substitutes for conventional gasoline and diesel fuels. These alternative fuels are characterized by elevated auto-ignition temperatures, typically at or above approximately 700K, and include hydrogen, compressed natural gas (CNG), and liquefied natural gas (LNG). Engines powered by hydrogen or natural gas offer several benefits. Notably, conventional internal combustion engines can typically operate on these fuels with minimal or no modifications. This compatibility facilitates adoption by leveraging established, reliable, and characterized engine architectures that have been refined over an extended period.

[0004] A significant technical challenge associated with hydrogen-fueled and natural gas-fueled engines, however, involves a phenomenon known as stochastic pre-ignition (SPI). This phenomenon represents a primary obstacle to the broader commercialization of internal combustion engines utilizing hydrogen or natural gas as fuel. SPI refers to an unintended premature combustion event of the primary fuel charge, which results in early detonation, misfiring, and engine knock. While SPI shares similarities with low-speed pre-ignition (LSPI), a condition commonly observed in turbocharged gasoline engines employing direct injection, established mitigation strategies effective against LSPI in conventional gasoline powertrains do not reliably address SPI in hydrogen or natural gas applications.

[0005] Previously it was believed that API Group III base oils combined with polymethacrylate (PMA) copolymers aided in the reduction of SPI in hydrogen fueled engines. According to US 2025 / 0263625, in a study that evaluated uncontrolled ignition in hydrogen engines at the Graz University of Technology, API Group II base oils performed worse in the context of SPI and API GIII base oils performed better. As explained in the evaluation of the '625 patent, the baseline lubricant with an API Group II base oil and olefin copolymer (e.g., Paratone 24EX that is believed to have 60 weight percent ethylene content, a weight average molecular weight of about 168,000 g / mol, and a polydispersity index of about 2.1) had very poor relative performance in total pre-ignition events in hydrogen fueled engines as compared to lubricants with API Group III base oils and / or lubricants with polymethacrylate (PMA) copolymers.SUMMARY

[0006] In one embodiment, a lubricating oil composition configured for lubricating an internal combustion engine fueled with a fuel having an auto-ignition temperature greater than about 700K is described. In one aspect, the lubricating oil composition included one or more base oils of lubricating viscosity; a viscosity modifier olefin copolymer having a weight average molecular weight of about 100,000 to about 200,000 g / mol and about 55 mol percent or less of ethylene monomer content; and wherein the lubricating oil composition includes at least about 0.8 weight percent based on active copolymer content, of the viscosity modifier olefin copolymer.

[0007] In other embodiments, the lubricating oil composition of the previous paragraph may include other features or embodiments in any combination. These other features or embodiment include one or more of the following: wherein the one or more base oils of lubricating viscosity includes one or more API Group III base oils; and / or wherein the viscosity modifier olefin copolymer has a weight average molecular weight of about 170,000 to about 200,000 g / mol; wherein lubricating oil composition further includes an overbased magnesium-containing metal detergent having a TBN of at least about 200 mg KOH / g (ASTM D2896) and providing about 1000 to about 3000 ppm of magnesium to the lubricating oil composition; and / or wherein the olefin copolymer includes about 45 to about 55 mol percent of ethylene monomer content and about 45 to about 55 mol percent of propylene monomer content; and / or wherein the lubricating oil composition includes about 0.8 weight percent to about 2 weight percent, based on active copolymer content, of the viscosity modifier olefin copolymer; and / or wherein the viscosity modifier olefin copolymer is diluted in an API Group I and / or Group II base oil, and wherein the viscosity modifier olefin copolymer is about 5 to about 15 weight percent of active copolymer in the API Group I and / or Group II base oil; and / or wherein the viscosity modifier olefin copolymer has a shear stability index as measured pursuant to ASTM D6278 of 18 to 26; and / or wherein the lubricating oil composition is substantially free of poly(meth)acrylate copolymers; and / or wherein the fuel having an auto-ignition temperature greater than about 700K is hydrogen fuel; and / or wherein the lubricating oil composition has an average measured stochastic pre-ignition (SPI) of about 50 SPI counts or less per 1000 cycles at 1350 rpm and 17 bar brake mean effective pressure (BMEP) when evaluated as described in the Examples; and / or wherein the lubricating oil composition has a KV100 of 13.5 cSt or less.

[0008] In another embodiment, a method of lubricating an internal combustion engine when fueled with a fuel having an auto-ignition temperature greater than about 700K to mitigate abnormal combustion events is described herein. In an aspect, the method includes lubricating a crankcase of an internal combustion engine with a lubricating oil composition and combusting a fuel having an auto-ignition temperature greater than about 700K in the internal combustion engine; and wherein the lubricating oil composition includes any embodiment of the lubricating composition as described in the previous two paragraphs.

[0009] In a further embodiment, a lubricating oil composition configured for lubricating an internal combustion engine fueled with a fuel having an auto-ignition temperature greater than about 700K is described herein wherein the lubricating oil composition includes one or more base oils of lubricating viscosity, wherein the one or more base oils include one or more API Group I base oils, one or more API Group II base oils, or combinations thereof, and an overbased magnesium-containing metal detergent having a TBN of at least about 200 mg KOH / g (ASTM D2896) and providing about 1000 to about 3000 ppm of magnesium to the lubricating oil composition.

[0010] In yet further embodiments, the lubricating oil composition of the previous paragraph may include other features or embodiments in any combination. These other features and embodiment include one or more of the following: wherein the lubricating oil composition includes at least about 0.7 weight percent, based on active content, of a viscosity modifier olefin copolymer having a weight average molecular weight of up to about 200,000 g / mol and about 55 mol percent or less of ethylene monomer content; and / or wherein the viscosity modifier olefin copolymer has a weight average molecular weight about 170,000 to about 200,000 g / mol; and / or wherein the wherein the lubricating oil composition has a KV100 of 11 cSt or less; and / or wherein the viscosity modifier olefin copolymer includes about 45 to about 55 mol percent of ethylene monomer content and about 45 to about 55 mol percent of propylene monomer content; and / or wherein the wherein the lubricating oil composition includes about 0.6 weight percent to about 2 weight percent, based on active copolymer content, of the viscosity modifier olefin copolymer; and / or wherein the viscosity modifier olefin copolymer is diluted in an API Group I and / or Group II base oil, and wherein the viscosity modifier olefin copolymer is about 5 to about 15 weight percent of active copolymer content in the API Group I or Group II base oil; and / or wherein the viscosity modifier olefin copolymer has a shear stability index as measured pursuant to ASTM D6278 of 18 to 26; and / or wherein the lubricating oil composition is substantially free of poly(meth)acrylate copolymers; and / or wherein the fuel having an auto-ignition temperature greater than about 700K is hydrogen fuel; and / or wherein the lubricating oil composition has an average measured stochastic pre-ignition (SPI) of about 65 SPI counts or less per 1000 cycles at 1350 rpm and 17 bar brake mean effective pressure (BMEP).

[0011] In yet another embodiment, a method of lubricating an internal combustion engine when fueled with a fuel having an auto-ignition temperature greater than about 700K to mitigate abnormal combustion events is also described herein wherein the method includes lubricating a crankcase of an internal combustion engine with a lubricating oil composition and combusting a fuel having an auto-ignition temperature greater than about 700K in the internal combustion engine; and wherein the lubricating oil composition includes a composition of any embodiment described in the previous two paragraphs.

[0012] In a further embodiment, a lubricating oil composition configured for lubricating an internal combustion engine fueled with a fuel having an auto-ignition temperature greater than about 700K is described herein wherein the lubricating oil composition includes one or more base oils of lubricating viscosity; and a viscosity modifier olefin copolymer having a weight average molecular weight of about 200,000 to about 500,000 g / mol, about 55 mol percent or less of ethylene monomer content, and a shear stability index as measured pursuant to ASTM D6278 of 50 to 55.

[0013] In yet other embodiments, the lubricating oil composition of the previous paragraph may include other features or embodiments in any combination. These other features or embodiment include one or more of the following: wherein the one or more base oils of lubricating viscosity includes one or more API Group I base oils, one or more API Group II base oils, one or more API Group III base oils, or combinations thereof, and / or wherein lubricating oil composition further includes an overbased magnesium-containing metal detergent having a TBN of at least about 200 (ASTM D2896) and providing about 1000 to about 3000 ppm of magnesium to the lubricating oil composition; and / or wherein the viscosity modifier olefin copolymer includes about 45 to about 55 mol percent of ethylene monomer content and about 45 to about 55 mol percent of propylene monomer content; and / or wherein the wherein the lubricating oil composition includes about 0.6 weight percent to about 2 weight percent, based on active copolymer content, of the viscosity modifier olefin copolymer; and / or wherein the viscosity modifier olefin copolymer is diluted in an API Group I and / or Group II base oil, and wherein the olefin copolymer is about 5 to about 15 weight percent of active copolymer content in the API Group I or Group II base oil; and / or wherein the lubricating oil composition is substantially free of poly(meth)acrylate copolymers; and / or wherein the fuel having an auto-ignition temperature greater than about 700K is hydrogen fuel; and / or wherein the lubricating oil composition has an average measured stochastic pre-ignition (SPI) of about 50 SPI counts or less per 1000 cycles at 1350 rpm and 17 bar brake mean effective pressure (BMEP) as described in the Examples.

[0014] In yet another embodiment, a method of lubricating an internal combustion engine when fueled with a fuel having an auto-ignition temperature greater than about 700K to mitigate abnormal combustion events is described herein and wherein the method includes lubricating a crankcase of an internal combustion engine with a lubricating oil composition and combusting a fuel having an auto-ignition temperature greater than about 700K in the internal combustion engine; and wherein the lubricating oil composition includes any embodiment as described in the previous two paragraphs.

[0015] In another embodiment, the use of any embodiment of the lubricating compositions as described in this Summary is also provided herein for achieving an average measured stochastic pre-ignition (SPI) of about 65 SPI counts or less or, in other embodiments, about 50 SPI counts or less per 1000 cycles at 1350 rpm and 17 bar brake mean effective pressure (BMEP) when evaluated as described in the Examples herein.

[0016] Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein.DETAILED DESCRIPTION

[0017] Stochastic pre-ignition (SPI) is a limiting factor in widespread use of alternative combustion fuels (as considered herein, fuels having an auto-ignition temperature of at least about 700K) in internal combustion engines. While SPI is a phenomenon that tends to be similar to low speed pre-ignition (LSPI) in gasoline engines that is sometimes confronted in certain turbocharged direct-injection engine gasoline engines, solutions to address LSPI in gasoline engines do not necessarily improve SPI in, for instance, hydrogen-fueled or natural gas-fueled internal combustion engines. Thus, conventional gasoline engine lubricants cannot necessarily be used in engines operated with the alternative combustion fuels, such as hydrogen-fueled engines or natural gas-fueled internal combustion engines.

[0018] According to exemplary embodiments, lubricating oil compositions are provided herein that are configured for use in or for methods of lubricating an internal combustion engine fueled with an alternative fuel having an auto-ignition temperature of at least about 700K (preferably, fuels having an auto-ignition temperature of 850K or above, and most preferably, hydrogen fuel). The lubricating oil compositions herein are effective to reduce SPI in engines fueled with such alternative fuels.

[0019] In one approach or embodiment, the lubricating oil compositions include one or more base oils of lubricating viscosity and a lower molecular weight viscosity modifier olefin copolymer. In one aspect, the lower molecular weight viscosity modifier olefin copolymer has a weight average molecular weight of up to about 200,000 g / mol (in other approaches, about 100,000 to about 200,000 g / mol) and includes about 55 mol percent or less of ethylene monomer content (in other embodiments, about 45 to about 55 mol percent, or about 48 to about 51 mol percent of ethylene monomer content). As shown in the Examples below, the use of such lower molecular weight viscosity modifier olefin copolymer, when the polymer used is of the molecular weight and / or percent ethylene monomer content specified, aids in the reduction of SPI. In other aspects, the lubricating oil compositions include at least about 0.8 weight percent, based on active copolymer content, of such lower molecular weight viscosity modifier olefin copolymer. As demonstrated in the Examples, this discovered amount, in some embodiments, may aid in reducing SPI. In other approaches of this embodiment, the one or more base oils of lubricating viscosity is one or more API Group III base oils.

[0020] In a second approach or embodiment, the lubricating oil compositions include base oils of lubricating viscosity selected from one or more API Group I base oils, one or more API Group II base oils, or combinations thereof that are widely accepted as lower quality base oils. The compositions of this second approach combine such lower quality base oils with an overbased magnesium-containing metal detergent (e.g., an overbased magnesium sulfonate detergent) having a TBN of at least about 200 mg KOH / g (ASTM D2896) and that provides about 4 to about 12 mmol of magnesium per 100 grams of the lubricating oil composition. In other approaches, the overbased magnesium-containing metal detergent provides at least about 1000 ppm of magnesium to the compositions (in other embodiments, about 1000 ppm to about 3000 ppm of magnesium or about 2000 ppm to about 3000 ppm of magnesium). This second embodiment may also include amounts of the lower molecular weight viscosity modifier olefin copolymer and, if included, the lubricating oil composition may include at least about 0.7 weight percent, based on active content, of the lower molecular weight viscosity modifier olefin copolymer having a weight average molecular weight of up to about 200,000 g / mol (in other approaches, about 100,000 to about 200,000 g / mol) and with about 55 mol percent or less of ethylene monomer content (in other embodiments, about 45 to about 55 mol percent, or about 48 to about 51 mol percent of ethylene monomer content). As shown in the Examples, the use of such amounts of the magnesium-containing detergent and the lower molecular weight viscosity modifier olefin copolymer aids in the reduction of SPI when combined with the lower quality API Group I and / or Group II base oils.

[0021] In a third approach or embodiment, the lubricating oil compositions include one or more base oils of lubricating viscosity and a viscosity modifier olefin copolymer having a higher molecular weight and, in this embodiment, the higher molecular weight viscosity modifier olefin copolymer has a weight average molecular weight greater than about 200,000 g / mol or, in other embodiments, greater than about 200,000 g / mol to about 500,000 g / mol, and in yet further embodiments, about 250,000 g / mol to about 350,000 g / mol. As shown in the Examples, the use of this higher molecular weight viscosity modifier olefin copolymer, when the polymer used is of the higher molecular weight, includes a certain percent ethylene monomer content, and / or specific shear stability index, may also aid in the reduction of SPI. Further, the higher molecular weight viscosity modifier olefin copolymer used in this embodiment, in addition to having the higher molecular weight, may also have a shear stability index, as measured pursuant to ASTM D6278, of 50 to 55. In other embodiments, the higher molecular weight viscosity modifier olefin copolymer may be diluted in about 85 to about 95 weight percent of an API Group I and / or Group II base oil.Viscosity Modifier

[0022] Embodiments of the lubricating oil compositions herein may include a viscosity modifier. The viscosity modifier is preferably an olefin copolymer having a certain molecular weight, ethylene monomer content, and / or shear stability index. The compositions herein are also preferably substantially free of poly(meth)acrylate (PMA) viscosity modifier polymers (in this context, substantially free means less than about 0.5 weight percent, less than about 0.1 weight percent, less than 0.05, or no detectable levels of PMA viscosity modifier polymers based on active PMA content). The term “olefin copolymer” or “OCP” as used herein refers to a polymer formed by copolymerizing two or more olefin monomers (e.g., ethylene and propylene) to create polymers with specific molecular weight distributions and compositions that modify the viscosity-temperature behavior of lubricating oils. The properties of the olefin copolymer used are characterized in part by the molecular weight of the polymer, the monomer content used (at least the ethylene monomer content), and in some instances, a shear stability index (e.g., SSI as measured pursuant to ASTM D6278). The ethylene monomer content of the olefin copolymers is one metric impacting performance, where the amount of ethylene balances the solubility in the base oils used, the thickening efficiency of the polymer, and the shear stability (for example, according to ASTM D6278). These are characteristics of the polymer that aid in balancing the lubrication properties of the resulting lubricating composition that unexpectedly helps mitigate SPI when used in lubricants for the alternative fueled engines as described herein. The polydispersity index (PDI) is another property that may be considered, where PDI is defined as the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn). A PDI of 1.0 represents a monodisperse polymer, while values above 1.0 indicate greater distribution of chain length. PDI may be determined by techniques such as gel permeation chromatography.

[0023] In one embodiment, the compositions herein utilize a lower molecular weight viscosity modifier olefin copolymer having a weight average molecular weight of up to about 200,000 g / mol. For example, the lower molecular weight viscosity modifier olefin copolymer may have a weight average molecular weight of about 100,000 to about 200,000 g / mol, preferably 125,000 to 175,000 g / mol, or more preferably 150,000 to 160,000 g / mol. The ethylene monomer content of this lower molecular weight copolymer is about 55 mol percent or less of ethylene monomer content. In some embodiments, the olefin copolymers herein include about 45 to about 55 mol percent of ethylene monomer content (or about 48 to about 51 mol percent of ethylene monomer content). Preferably, the remainder of the monomer content includes propylene monomers; for example, about 45 to about 55 mol percent of propylene monomer content based on the total copolymer. The lower molecular weight olefin copolymer of this aspect has a polydispersity index of over 1.2, preferably greater than 1.5. For example, the PDI may be 1.5 to 2.0. In yet other embodiments, this lower molecular weight olefin copolymer has a shear stability index SSI as measured pursuant to ASTM D6278 of about 18 to about 26 or, preferably about 20 to about 24. The lower molecular weight olefin copolymer may be diluted, in some embodiments, in about 85 to about 95 weight percent of an API Group I and / or Group II base oil.

[0024] In one embodiment, suitable amounts of the lower molecular weight viscosity modifier olefin copolymer used in the lubricating oil composition is at least about 0.8 weight percent, based on active copolymer content, of the viscosity modifier olefin copolymer. In other embodiments, the lower molecular weight viscosity modifier olefin copolymer is used in amounts of at least about 1.0 weight percent, or in other embodiments, about 0.8 weight percent to about 2 weight percent based on active polymer content, and more preferably about 1.5 to about 2.0 weight percent based on active polymer content. Preferably, such amounts of the lower molecular weight viscosity modifier olefin copolymer are suitable for use with an API Group III base oil.

[0025] In an alternative embodiment, the lubricating oil composition includes at least about 0.7 weight percent, based on active copolymer content, of the lower molecular weight viscosity modifier olefin copolymer. For instance, the lubricating oil compositions herein may include at least about 0.7 weight percent of such olefin copolymer having a weight average molecular weight of up to about 200,000 g / mol and about 55 mol percent or less of ethylene monomer content (in other approaches, about 45 to about 55 mol percent of ethylene monomer content, or about 48 to about 51 mol percent of ethylene monomer conent). Preferably, such amounts of the lower molecular weight copolymer are most suitable for use with an API Group I or Group II base oil and when preferably combined with select amounts of magnesium from detergents (as discussed more below). In other embodiments, the lower molecular weight viscosity modifier olefin copolymer is used in amounts of about 0.7 weight percent to about 2 weight percent based on active polymer content, and more preferably about 0.7 to about 1.5 weight percent based on active polymer content along with the API Group I and / or Group II base oils.

[0026] In a further embodiment, the lower molecular weight viscosity modifier olefin copolymer is provided in the lubricating oil composition along with a diluent. In various embodiments, the diluent is an API Group I and / or Group II base oil. In embodiments, the lower molecular weight viscosity modifier olefin copolymer described herein may be about 5 to about 15 weight percent of the active copolymer content in the API Group I and / or Group II base oil as diluent. In a further embodiment, the lower molecular weight viscosity modifier olefin copolymer, when diluted in the API Group I and / or Group II base oil, has a shear stability index as measured pursuant to ASTM D6278 of 18 to 26 (or 20 to 24).

[0027] In another embodiment, a higher molecular weight viscosity modifier olefin copolymer may be used in the lubricating compositions of the present disclosure. In an aspect, the higher molecular weight viscosity modifier olefin copolymer has a weight average molecular weight of greater than 200,000 g / mol or greater than about 200,000 to about 500,000 g / mol. For example, a weight average molecular weight of about 250,000 to about 350,000 g / mol, preferably 270,000 to 290,000 g / mol. The ethylene monomer content of this higher molecular weight olefin copolymer is about 55 mol percent or less of ethylene monomer content. In some embodiments, this higher molecular weight olefin copolymer includes about 45 to about 55 mol percent of ethylene monomer content (or about 48 to about 51 mol percent). Preferably, the remainder of the monomer content of the higher molecular weight copolymer includes a propylene monomer; for example, about 45 to about 55 mol percent of propylene monomer content based on the total copolymer. The higher molecular weight olefin copolymer may also have a polydispersity index of over 1.2, preferably greater than 1.5. For example, the PDI may be about 1.8 to about 2.2 or about 2.0 to about 2.5. In yet other embodiments, the higher molecular weight olefin copolymers have a shear stability index SSI as measured pursuant to ASTM D6278 of about 50 to about 55 or, preferably about 51 to about 54. In embodiment, the higher molecular weight olefin copolymers may also be diluted in about 85 to about 95 weight percent of an API Group I and / or Group II base oil.

[0028] The amount of the higher molecular weight olefin copolymer, when used in the lubricating oil compositions herein, is preferably at least about 0.4 weight percent, based on active copolymer content. In further embodiments, the higher molecular weight olefin copolymer is used in the lubricating compositions in amounts, based on active polymer content, of greater than about 0.6 weight percent, and preferably about 0.4 to about 2.0 weight percent or more preferably about 0.6 to about 2.0 weight percent based on active copolymer content in the compositions and, most preferably, about 0.6 to about 1.0 weight percent based on active copolymer content. This higher molecular weight olefin copolymer may be used with an API Group I, Group II, and / or Group III base oil.

[0029] In a further embodiment, the higher molecular wight viscosity modifier olefin copolymer may also be provided along with a diluent. In various embodiments, the diluent suitable for the higher molecular weight viscosity modifier olefin copolymer is also an API Group I and / or Group II base oil. In further embodiments, the higher molecular weight viscosity modifier olefin copolymer is about 5 to about 15 weight percent of active copolymer content in the API Group I and / or Group II base oil as diluent.Base Oil:

[0030] The lubricating oil compositions herein include one or more base oils having a lubricating viscosity. Base oils suitable for use in formulating the lubricating oil compositions suitable for use in lubricating an internal combustion engine fueled with the alternative fuels as described herein may be selected from any suitable synthetic or natural oils or mixtures thereof having a suitable lubricating viscosity. Natural oils may include animal oils and vegetable oils (e.g., castor oil, lard oil) as well as mineral oils such as liquid petroleum oils and solvent treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic types. Oils derived from coal or shale may also be suitable. Further, oil derived from a gas-to-liquid process is also suitable. The base oil may have a kinematic viscosity at 100° C. (e.g. KV100) of about 2 to about 15 cSt, as measured by ASTM D2270-10.

[0031] The base oil as used in lubricants described herein may be a single base oil or may be a mixture of two or more base oils. In one embodiment, the one or more base oil(s) may be selected from any of the base oils in Groups I to IV as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. In other embodiments, the one or more base oils of lubricating viscosity preferably include only API Group I base oils, API Group II base oils, or combinations thereof. Preferably, the one or more base oils of lubricating viscosity includes one or more API Group I base oils, one or more API Group II base oils, and one or more API Group III base oils. In some embodiments, the one or more base oils of lubricating viscosity includes one or more API Group III base oils. In alternative embodiments, the one or more base oils include one or more API Group I base oils, one or more API Group II base oils, or combinations thereof. In alternative embodiments, the one or more base oils include one or more API Group II base oil. As discussed more below, if API Group I and / or API Group II base oils are used (which are widely accepted as lower quality base oils), the lubricating oil compositions herein also include select amounts of magnesium metal, which unexpectedly overcomes any negative performance debits of the lower quality base oils. Such base oil groups are shown in Table 1 as follows:TABLE 1Base oil CategorySulfur (%)Saturates (%)Viscosity IndexAPI Group I>0.03and / or<9080 to 120API Group II≤0.03and≥9080 to 120API Group III≤0.03and≥90≥120API Group IVAll polyalphaolefins (PAOs)API Group VAll others not included inGroups I, II, III, or IV

[0032] API Group III base oils may include oil derived from Fischer-Tropsch synthesized hydrocarbons. Fischer-Tropsch synthesized hydrocarbons are made from synthesis gas containing H2 and CO using a Fischer-Tropsch catalyst. Such hydrocarbons typically require further processing in order to be useful as the base oil. These types of oils are commonly referred to as gas-to-liquids (GTLs). For example, the hydrocarbons may be hydroisomerized using processes disclosed in U.S. Pat. No. 6,103,099 or 6,180,575; hydrocracked and hydroisomerized using processes disclosed in U.S. Pat. No. 4,943,672 or 6,096,940; dewaxed using processes disclosed in U.S. Pat. No. 5,882,505; or hydroisomerized and dewaxed using processes disclosed in U.S. Pat. Nos. 6,013,171; 6,080,301; or 6,165,949.

[0033] API Group IV base oils, PAOs, are typically derived from monomers having from 4 to 30, or from 4 to 20, or from 6 to 16 carbon atoms. Examples of PAOs that may be used in the present invention include those derived from octene, decene, mixtures thereof, and the like. PAOs may have a kinematic viscosity of from 2 to 15, or from 3 to 12, or from 4 to 8 cSt at 100° C., as measured by ASTM D2270-10. Examples of PAOs include 4 cSt at 100° C. PAOs, 6 cSt at 100° C. PAOs, and mixtures thereof.

[0034] The base oil(s) are combined with an additive composition as disclosed in embodiments herein to provide a lubricating oil composition for lubricating the crankcase of an internal combustion engine fueled with a gaseous fuel having an auto-ignition temperature greater than about 700K. Accordingly, the base oil may be present in the lubricating oil composition in an amount greater than about 75 wt % based on the total weight of the lubricating oil composition. In some embodiments, the base oil may be present in the lubricating oil composition in an amount greater than about 80 wt % based on the total weight of the lubricating oil composition. In some embodiments, the base oil may be present in the lubricating oil composition in an amount greater than about 85 wt % based on the total weight of the lubricating oil composition.Detergent System

[0035] The detergent systems of the lubricating oil compositions herein include one or more metal-containing detergents, preferably one or more overbased based metal-containing detergents, and more preferably one or more overbased magnesium-containing detergent providing a certain content of magnesium to the compositions. In one embodiment, the overbased magnesium-containing detergent(s) provide at least about 2 mmol of magnesium per 100 grams of lubricant, and more preferably about 4 to about 12 mmol of magnesium per 100 grams of the lubricating compositions herein as discussed more below (and, in some embodiments, at least about 1000 ppm of magnesium, or about 1000 ppm to about 3000 ppm of magnesium, or about 2000 ppm to about 3000 ppm, or about 2500 ppm to about 3000 ppm of magnesium). In some embodiments, the overbased detergents herein have a total base number (TBN) of at least about 200 mg KOH / g (preferably about 240 to about 450 mg KOH / g or about 250 to about 420 mg KOH / g) measured by ASTM D2896, and if used, neutral to low-based or neutral detergents have a total base number (TBN) of 50 mg KOH / g or below as measured by ASTM D2896. Suitable detergents and their methods of preparation are described, for instance, in greater detail in numerous patent publications, including U.S. Pat. Nos. 7,732,390; 4,165,291, and / or 4,206,062 (and references cited therein), which are incorporated herein by reference.

[0036] In embodiments, suitable detergent substrates (e.g., sulfonates or phenates) may be salted with an alkali or alkaline earth metal, which is preferably magnesium. In approaches or embodiments, the detergent systems herein preferably include an overbased magnesium-containing metal detergent having a TBN of at least about 200 (ASTM D2896) (preferably providing at least about 2 mmol or about 4 to about 12 mmol of magnesium per 100 grams of lubricant) to the lubricating oil composition. In other approaches or embodiments, the detergent systems provide at least about 1000 ppm of magnesium (or, as discussed above, about 1000 ppm to about 3000 ppm of magnesium, or about 2000 ppm to about 3000 ppm, or about 2500 ppm to about 3000 ppm of magnesium). In a further embodiment, the overbased magnesium-based detergent is an overbased magnesium sulfonate detergent.

[0037] In embodiments and subject to the discussions on the detergent systems herein, suitable detergents may include linear or branched alkali or alkaline earth metal salts, such as calcium, sodium, or magnesium salts, of petroleum sulfonic acids and long chain mono- or di-alkylaryl sulfonic acids with the aryl group being benzyl, tolyl, and xylyl and / or various phenates or derivatives of phenates. Examples of suitable detergents include (subject to the noted TBN and metal limitations discussed herein), but are not limited to, low-based, neutral, and / or overbased variations of the following detergents: magnesium phenates, magnesium sulfur containing phenates, magnesium sulfonates, magnesium calixarates, magnesium salixarates, magnesium salicylates, magnesium carboxylic acids, magnesium phosphorus acids, magnesium mono- and / or di-thiophosphoric acids, magnesium alkyl phenols, magnesium sulfur coupled alkyl phenol compounds, magnesium methylene bridged phenols, calcium phenates, calcium sulfur containing phenates, calcium sulfonates, calcium calixarates, calcium salixarates, calcium salicylates, calcium carboxylic acids, calcium phosphorus acids, calcium mono- and / or di-thiophosphoric acids, calcium alkyl phenols, calcium sulfur coupled alkyl phenol compounds, calcium methylene bridged phenols, sodium phenates, sodium sulfur containing phenates, sodium sulfonates, sodium calixarates, sodium salixarates, sodium salicylates, sodium carboxylic acids, sodium phosphorus acids, sodium mono- and / or di-thiophosphoric acids, sodium alkyl phenols, sodium sulfur coupled alkyl phenol compounds, or sodium methylene bridged phenols. Preferably, the detergent systems herein include at least overbased magnesium detergents providing the metal amounts noted above.

[0038] The terminology “overbased” relates to metal salts, wherein the amount of metal present exceeds the stoichiometric amount. Such salts may have a conversion level in excess of 100% (i.e., they may comprise more than 100% of the theoretical amount of metal needed to convert the acid to its “normal,”“neutral” salt). The expression “metal ratio,” often abbreviated as MR, is used to designate the ratio of total chemical equivalents of metal in the overbased salt to chemical equivalents of the metal in a neutral salt according to known chemical reactivity and stoichiometry. In a normal or neutral salt, the metal ratio is one and in an overbased salt, MR, is greater than one. They are commonly referred to as overbased, hyperbased, or superbased salts and may be salts of organic sulfur acids. As used herein, an overbased detergent herein may have, in one embodiment, a total base number (TBN) of about 200 mg KOH / gram or higher, about 240 mg KOH / gram or greater, about 250 mg KOH / gram or greater, about 280 mg KOH / gram or greater, or about 300 mg KOH / gram or greater (in other approaches, about 240 to about 450 mg KOH / g or about 250 to about 420 mg KOH / g). As used herein, total base number or TBN of a detergent additive is determined using ASTM D2896. When such detergent compositions are formed in an inert diluent, e.g. a process oil, usually a mineral oil, the total base number reflects the basicity of the overall composition including diluent, and any other materials (e.g., promoter, etc.) that may be contained in the detergent composition.

[0039] Examples of suitable overbased detergents include (subject to the TBN and metal limitations noted herein), but are not limited to, overbased magnesium phenates, overbased magnesium sulfur containing phenates, overbased magnesium sulfonates, overbased magnesium calixarates, overbased magnesium salixarates, overbased magnesium salicylates, overbased magnesium carboxylic acids, overbased magnesium phosphorus acids, overbased magnesium mono- and / or di-thiophosphoric acids, overbased magnesium alkyl phenols, overbased magnesium sulfur coupled alkyl phenol compounds, or overbased magnesium methylene bridged phenols.

[0040] In some embodiments, the detergent systems used in the lubricants herein includes an overbased magnesium detergent (preferably an overbased magnesium sulfonate detergent) having a total base number (TBN) of at least about 200 mg KOH / g and, in other approaches, a TBN of about 200 to about 450 and, in other approaches, about 200 to about 425 or about 250 to about 425, or about 280 to about 425 (ASTM D2896). The above described TBN values reflect those of finished detergent components that have been diluted in a base oil.

[0041] In other embodiments, the detergent systems include select amounts of such overbased magnesium-containing metal detergents (e.g., overbased magnesium sulfonate detergents) to provide at least about 2 mmol or about 2 to about 12 mmol of magnesium, in other approaches, about 4 to about 12 mmol of magnesium, or about 6 to about 12 mmol of magnesium to the lubricating oil compositions herein, or about 8 to about 12 mmol of magnesium per 100 grams of lubricant. As shown in the Examples below, having such minimum amounts of magnesium is advantageous to counteract any negative performance benefits of the lower quality API Group I and / or Group II base oils. In yet other approaches, the lubricants herein include at least about 1000 ppm of magnesium, at least about 1500 ppm of magnesium, or at least about 2000 ppm of magnesium (and preferably about 5000 ppm or less, about 4500 ppm or less, about 4000 ppm or less, about 3500 ppm or less of magnesium, or about 3000 ppm or less). In other approaches or embodiments, the lubricants include about 1000 ppm of magnesium to about 3000 ppm of magnesium, or about 2000 ppm to about 3000 ppm of magnesium, or about 2500 ppm to about 3000 ppm of magnesium. As shown in the Examples, it was surprising that magnesium contributions could overcome performance deficiencies of the lower quality base oils in the context of SPI in hydrogen-fueled engines.Lubricating Oil Compositions:

[0042] The lubricating oil composition herein include one or more of a select base oil blend, a specific viscosity modifier olefin copolymer and / or select detergent system. The inclusion of either the lower molecular weight and / or or higher molecular weight viscosity modifier olefin copolymer aids, in some approaches, in achieving one or more of the desired viscosity (KV100 and / or HTHS), NOACK, and / or low SPI of the resulting lubricating oil compositions when used to lubricate the alternative fueled engines as shown in the Example below. Other approaches combine the base oil(s) and the viscosity modifier olefin copolymer with a select detergent system to minimize SPI in such alternative fueled engines.

[0043] The resulting viscosity can be measured, for example, by measuring its KV100 and / or high temperature high shear viscosity (HTHS). KV100 refers to the kinematic viscosity of a lubricating composition measured at 100° C., typically expressed in mm2 / s or centistokes (cSt), as determined in accordance with ASTM D445 or an equivalent standard method. In one embodiment, the lubricating oil compositions herein has a kinematic viscosity at 100° C. (KV100) of about 14 cSt or less, or about 13.5 cSt or less, or in another embodiments, about 11 cSt or less (preferably, about 6 to about 14 cSt or about 6 to about 11 cSt). High Temperature High Shear (HTHS) viscosity refers to a dynamic viscosity under high shear conditions and is also typically reported in cSt, as determined in accordance with one or more of ASTM D4683, D4741, and / or D5471. In one embodiment, the lubricating oil compositions herein has a HTHS viscosity at 150° C. of about 4.0 cSt or less, or in another embodiments, about 3.7 cSt or less (preferably, about 2.3 to about 3.7 cSt or about 2.6 to about 3.5 cSt).

[0044] NOACK volatility measures engine oil evaporation loss at higher temperatures (200° C. for 1 hour) and is reported as percent or weight fraction lost as determined in accordance with ASTM D5800. In one embodiment, the lubricating oil compositions herein have a NOACK volatility (200° C. for 1 hour) about 20% or less, or in another embodiments, about 18% or less, or about 15% or less, or about 13.5% or less (preferably, about 12 to about 18% or about 12 to about 16%).

[0045] Stochastic pre-ignition (SPI) refers to an unintended premature combustion event of the primary fuel charge, which results in early detonation, misfiring, and engine knock. SPI for a hydrogen-fueled internal combustion engine may be evaluated at the Graz University of Technology (Austria) and is reported as events per 1000 cycles at 1350 rpm and 17 bar brake mean effective pressure (BMEP). In one embodiment, the lubricating oil compositions herein achieve about 65 SPI counts or less per 1000 cycles, or about 50 SPI counts or less per 1000 cycles, or about 40 SPI counts or less per 1000 cycles, or about 20 SPI counts or less per 1000 cycles. When the base oil, detergent, and / or viscosity modifier is not correctly selected, the SPI events increase to undesirable levels (which is generally greater than 100 SPI events per 1000 cycles).Alternative Combustion Fuels

[0046] The lubricating oil compositions herein are configured for lubricating the crankcase of an internal combustion engine being fueled with an alternative combustion fuel, which for purposes of this disclosure, is a fuel having an auto-ignition temperature of at least about 700K, at least about 800K, or at least about 850K. In other approaches, the alternative combustion fuels have auto-ignition temperatures of up to about 900K, up to about 880K, or up to about 860K. Such alternative combustion fuels include, but are not limited to, hydrogen fuel (auto-ignition temperature of about 858K) that can be gaseous hydrogen fuel, natural gas fuel (auto-ignition temperature of about 813K) that can be compressed natural gas and / or liquid natural gas, and the like. In some embodiments, the fuel having an auto-ignition temperature greater than about 700K is hydrogen fuel. Preferably, the alternative combustion fuels herein that are suited for use with the lubricating compositions herein include gaseous hydrogen fuel that is combusted in the engine in a gaseous state.

[0047] In some aspects, this disclosure provides a method for the lubrication of a crankcase of an internal combustion engine with a lubricating oil composition and combusting a fuel having an auto-ignition temperature greater than about 700K in the internal combustion engine.Other Additives

[0048] The lubricating oil compositions described herein may also include other additives of the type used in crankcase lubricating compositions in addition to the viscosity modifier(s), detergent(s), and other components described above. Such additives include, but are not limited to, antioxidant(s), phosphorus-containing components, corrosion inhibitor(s), antirust additives, antifoam agent(s), demulsifier(s), pour point depressant(s), seal swell agent(s), and additional dispersant(s), additional friction modifier(s), and additional sulfur-containing component(s).

[0049] DISPERSANTS: The lubricating oil composition may optionally include one or more dispersants or mixtures thereof. Dispersants are often known as ashless-type dispersants because, prior to mixing in a lubricating oil composition, they do not contain ash-forming metals and they do not normally contribute any ash when added to a lubricant. Ashless type dispersants are characterized by a polar group attached to a relatively high molecular weight hydrocarbon chain. Typical ashless dispersants include N-substituted long chain alkenyl succinimides. Examples of N-substituted long chain alkenyl succinimides include polyisobutylene succinimide with the number average molecular weight of the polyisobutylene substituent being in the range about 350 to about 50,000, or to about 5,000, or to about 3,000, as measured by GPC. Succinimide dispersants and their preparation are disclosed, for instance in U.S. Pat. No. 7,897,696 or U.S. Pat. No. 4,234,435. The alkenyl substituent may be prepared from polymerizable monomers containing about 2 to about 16, or about 2 to about 8, or about 2 to about 6 carbon atoms. Succinimide dispersants are typically the imide formed from a polyamine, typically a poly(ethyleneamine).

[0050] Preferred amines are selected from polyamines and hydroxyamines. Examples of polyamines that may be used include, but are not limited to, diethylene triamine (DETA), triethylene tetramine (TETA), tetraethylene pentamine (TEPA), and higher homologues such as pentaethylamine hexamine (PEHA), and the like.

[0051] A suitable heavy polyamine is a mixture of polyalkylene-polyamines comprising small amounts of lower polyamine oligomers such as TEPA and PEHA (pentaethylene hexamine) but primarily oligomers with 6 or more nitrogen atoms, 2 or more primary amines per molecule, and more extensive branching than conventional polyamine mixtures. A heavy polyamine preferably includes polyamine oligomers containing 7 or more nitrogens per molecule and with 2 or more primary amines per molecule. The heavy polyamine comprises more than 28 wt. % (e.g. >32 wt. %) total nitrogen and an equivalent weight of primary amine groups of 120-160 grams per equivalent.

[0052] In some approaches, suitable polyamines are commonly known as PAM and contain a mixture of ethylene amines where TEPA and pentaethylene hexamine (PEHA) are the major part of the polyamine, usually less than about 80%.

[0053] Typically, PAM has 8.7 to 8.9 milliequivalents of primary amine per gram (an equivalent weight of 115 to 112 grams per equivalent of primary amine) and a total nitrogen content of about 33-34 wt. %. Heavier cuts of PAM oligomers with practically no TEPA and only very small amounts of PEHA but containing primarily oligomers with more than 6 nitrogens and more extensive branching, may produce dispersants with improved dispersancy.

[0054] In an embodiment the present disclosure further comprises at least one polyisobutylene succinimide dispersant derived from polyisobutylene with a number average molecular weight in the range about 350 to about 50,000, or to about 5000, or to about 3000, as determined by GPC. The polyisobutylene succinimide may be used alone or in combination with other dispersants.

[0055] In some embodiments, polyisobutylene, when included, may have greater than 50 mol %, greater than 60 mol %, greater than 70 mol %, greater than 80 mol %, or greater than 90 mol % content of terminal double bonds. Such PIB is also referred to as highly reactive PIB (“HR-PIB”). HR-PIB having a number average molecular weight ranging from about 800 to about 5000, as determined by GPC, is suitable for use in embodiments of the present disclosure. Conventional PIB typically has less than 50 mol %, less than 40 mol %, less than 30 mol %, less than 20 mol %, or less than 10 mol % content of terminal double bonds.

[0056] An HR-PIB having a number average molecular weight ranging from about 900 to about 3000 may be suitable, as determined by GPC. Such HR-PIB is commercially available, or can be synthesized by the polymerization of isobutene in the presence of a non-chlorinated catalyst such as boron trifluoride, as described in U.S. Pat. No. 4,152,499 to Boerzel, et al. and U.S. Pat. No. 5,739,355 to Gateau, et al. When used in the aforementioned thermal ene reaction, HR-PIB may lead to higher conversion rates in the reaction, as well as lower amounts of sediment formation, due to increased reactivity. A suitable method is described in U.S. Pat. No. 7,897,696.

[0057] In one embodiment, the present disclosure further comprises at least one dispersant derived from polyisobutylene succinic anhydride (“PIBSA”). The PIBSA may have an average of between about 1.0 and about 2.0 succinic acid moieties per polymer. The % actives of the alkenyl or alkyl succinic anhydride can be determined using a chromatographic technique. This method is described in column 5 and 6 in U.S. Pat. No. 5,334,321. The percent conversion of the polyolefin is calculated from the % actives using the equation in column 5 and 6 in U.S. Pat. No. 5,334,321. Unless stated otherwise, all percentages are in weight percent and all molecular weights are number average molecular weights determined by gel permeation chromatography (GPC) using commercially available polystyrene standards (with a number average molecular weight of 180 to about 18,000 as the calibration reference).

[0058] In one embodiment, the dispersant may be derived from a polyalphaolefin (PAO) succinic anhydride. In one embodiment, the dispersant may be derived from olefin maleic anhydride copolymer. As an example, the dispersant may be described as a poly-PIBSA. In an embodiment, the dispersant may be derived from an anhydride which is grafted to an ethylene-propylene copolymer.

[0059] A suitable class of nitrogen-containing dispersants may be derived from olefin copolymers (OCP), more specifically, ethylene-propylene dispersants which may be grafted with maleic anhydride. A more complete list of nitrogen-containing compounds that can be reacted with the functionalized OCP are described in U.S. Pat. Nos. 7,485,603; 7,786,057; 7,253,231; 6,107,257; and 5,075,383; and / or are commercially available.

[0060] One class of suitable dispersants may also be Mannich bases. Mannich bases are materials that are formed by the condensation of a higher molecular weight, alkyl-substituted phenol, a polyalkylene polyamine, and an aldehyde such as formaldehyde. Mannich bases are described in more detail in U.S. Pat. No. 3,634,515.

[0061] A suitable class of dispersants may also be high molecular weight esters or half ester amides. A suitable dispersant may also be post-treated by conventional methods by a reaction with any of a variety of agents. Among these are boron, urea, thiourea, dimercaptothiadiazoles, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, maleic anhydride, nitriles, epoxides, carbonates, cyclic carbonates, hindered phenolic esters, and phosphorus compounds. U.S. Pat. Nos. 7,645,726; 7,214,649; and 8,048,831 are incorporated herein by reference in their entireties.

[0062] In addition to the carbonate and boric acids post-treatments both the compounds may be post-treated, or further post-treatment, with a variety of post-treatments designed to improve or impart different properties. Such post-treatments include those summarized in columns 27-29 of U.S. Pat. No. 5,241,003, hereby incorporated by reference. Such treatments include, treatment with: Inorganic phosphorous acids or anhydrates (e.g., U.S. Pat. Nos. 3,403,102 and 4,648,980); Organic phosphorous compounds (e.g., U.S. Pat. No. 3,502,677); Phosphorous pentasulfides; Boron compounds as already noted above (e.g., U.S. Pat. Nos. 3,178,663 and 4,652,387); Carboxylic acid, polycarboxylic acids, anhydrides and / or acid halides (e.g., U.S. Pat. Nos. 3,708,522 and 4,948,386); Epoxides polyepoxiates or thioexpoxides (e.g., U.S. Pat. Nos. 3,859,318 and 5,026,495); Aldehyde or ketone (e.g., U.S. Pat. No. 3,458,530); Carbon disulfide (e.g., U.S. Pat. No. 3,256,185); Glycidol (e.g., U.S. Pat. No. 4,617,137); Urea, thiourea or guanidine (e.g., U.S. Pat. Nos. 3,312,619; 3,865,813; and British Patent GB 1,065,595); Organic sulfonic acid (e.g., U.S. Pat. No. 3,189,544 and British Patent GB 2,140,811); Alkenyl cyanide (e.g., U.S. Pat. Nos. 3,278,550 and 3,366,569); Diketene (e.g., U.S. Pat. No. 3,546,243); A diisocyanate (e.g., U.S. Pat. No. 3,573,205); Alkane sultone (e.g., U.S. Pat. No. 3,749,695); 1,3-Dicarbonyl Compound (e.g., U.S. Pat. No. 4,579,675); Sulfate of alkoxylated alcohol or phenol (e.g., U.S. Pat. No. 3,954,639); Cyclic lactone (e.g., U.S. Pat. Nos. 4,617,138; 4,645,515; 4,668,246; 4,963,275; and 4,971,711); Cyclic carbonate or thiocarbonate linear monocarbonate or polycarbonate, or chloroformate (e.g., U.S. Pat. Nos. 4,612,132; 4,647,390; 4,648,886; 4,670,170); Nitrogen-containing carboxylic acid (e.g., U.S. Pat. No. 4,971,598 and British Patent GB 2,140,811); Hydroxy-protected chlorodicarbonyloxy compound (e.g., U.S. Pat. No. 4,614,522); Lactam, thiolactam, thiolactone or dithiolactone (e.g., U.S. Pat. Nos. 4,614,603 and 4,666,460); Cyclic carbonate or thiocarbonate, linear monocarbonate or polycarbonate, or chloroformate (e.g., U.S. Pat. Nos. 4,612,132; 4,647,390; 4,646,860; and 4,670,170); Nitrogen-containing carboxylic acid (e.g., U.S. Pat. No. 4,971,598 and British Patent GB 2,440,811); Hydroxy-protected chlorodicarbonyloxy compound (e.g., U.S. Pat. No. 4,614,522); Lactam, thiolactam, thiolactone or dithiolactone (e.g., U.S. Pat. Nos. 4,614,603, and 4,666,460); Cyclic carbamate, cyclic thiocarbamate or cyclic dithiocarbamate (e.g., U.S. Pat. Nos. 4,663,062 and 4,666,459); Hydroxyaliphatic carboxylic acid (e.g., U.S. Pat. Nos. 4,482,464; 4,521,318; 4,713,189); Oxidizing agent (e.g., U.S. Pat. No. 4,379,064); Combination of phosphorus pentasulfide and a polyalkylene polyamine (e.g., U.S. Pat. No. 3,185,647); Combination of carboxylic acid or an aldehyde or ketone and sulfur or sulfur chloride (e.g., U.S. Pat. Nos. 3,390,086; 3,470,098); Combination of a hydrazine and carbon disulfide (e.g. U.S. Pat. No. 3,519,564); Combination of an aldehyde and a phenol (e.g., U.S. Pat. Nos. 3,649,229; 5,030,249; 5,039,307); Combination of an aldehyde and an O-diester of dithiophosphoric acid (e.g., U.S. Pat. No. 3,865,740); Combination of a hydroxyaliphatic carboxylic acid and a boric acid (e.g., U.S. Pat. No. 4,554,086); Combination of a hydroxyaliphatic carboxylic acid, then formaldehyde and a phenol (e.g., U.S. Pat. No. 4,636,322); Combination of a hydroxyaliphatic carboxylic acid and then an aliphatic dicarboxylic acid (e.g., U.S. Pat. No. 4,663,064); Combination of formaldehyde and a phenol and then glycolic acid (e.g., U.S. Pat. No. 4,699,724); Combination of a hydroxyaliphatic carboxylic acid or oxalic acid and then a diisocyanate (e.g. U.S. Pat. No. 4,713,191); Combination of inorganic acid or anhydride of phosphorus or a partial or total sulfur analog thereof and a boron compound (e.g., U.S. Pat. No. 4,857,214); Combination of an organic diacid then an unsaturated fatty acid and then a nitrosoaromatic amine optionally followed by a boron compound and then a glycolating agent (e.g., U.S. Pat. No. 4,973,412); Combination of an aldehyde and a triazole (e.g., U.S. Pat. No. 4,963,278); Combination of an aldehyde and a triazole then a boron compound (e.g., U.S. Pat. No. 4,981,492); Combination of cyclic lactone and a boron compound (e.g., U.S. Pat. Nos. 4,963,275 and 4,971,711). The above-mentioned patents are herein incorporated in their entireties.

[0063] The TBN of a suitable dispersant may be from about 10 to about 65 mg KOH / g dispersant, on an oil-free basis, which is comparable to about 5 to about 30 TBN if measured on a dispersant sample containing about 50% diluent oil. TBN is measured by the method of ASTM D2896.

[0064] In yet other embodiments, the optional dispersant additive may be a hydrocarbyl substituted succinamide or succinimide dispersant. In approaches, the hydrocarbyl substituted succinamide or succinimide dispersant may be derived from a hydrocarbyl substituted acylating agent reacted with a polyalkylene polyamine and wherein the hydrocarbyl substituent of the succinamide or the succinimide dispersant is a linear or branched hydrocarbyl group having a number average molecular weight of about 250 to about 5,000 as measured by GPC using polystyrene as a calibration reference.

[0065] In some approaches, the polyalkylene polyamine used to form the dispersant has the Formulawherein each R and R′, independently, is a divalent C1 to C6 alkylene linker, each R1 and R2, independently, is hydrogen, a C1 to C6 alkyl group, or together with the nitrogen atom to which they are attached form a 5- or 6-membered ring optionally fused with one or more aromatic or non-aromatic rings, and n is an integer from 0 to 8. In other approaches, the polyalkylene polyamine is selected from the group consisting of a mixture of polyethylene polyamines having an average of 5 to 7 nitrogen atoms, triethylenetetramine, tetraethylenepentamine, and combinations thereof.The dispersant, if present, can be used in an amount sufficient to provide up to about 20 wt %, based upon the final weight of the lubricating oil composition. Another amount of the dispersant that can be used may be about 0.1 wt % to about 15 wt %, or about 0.1 wt % to about 10 wt %, about 0.1 to 8 wt %, or about 1 wt % to about 10 wt %, or about 1 wt % to about 8 wt %, or about 1 wt % to about 6 wt %, based upon the final weight of the lubricating oil composition. In some embodiments, the lubricating oil composition utilizes a mixed dispersant system. A single type or a mixture of two or more types of dispersants in any desired ratio may be used.

[0067] ANTIWEAR AGENTS: The lubricating oil compositions herein also may optionally contain one or more antiwear agents. Examples of suitable antiwear agents include, but are not limited to, a metal thiophosphate; a metal dialkyldithiophosphate; a phosphoric acid ester or salt thereof, a phosphate ester(s); a phosphite; a phosphorus-containing carboxylic ester, ether, or amide; a sulfurized olefin; thiocarbamate-containing compounds including, thiocarbamate esters, alkylene-coupled thiocarbamates, dithiocarbamates, and / or bis(S-alkyldithiocarbamyl) disulfides; and mixtures thereof. A suitable antiwear agent may be a molybdenum dithiocarbamate, bis(dialkyl-dithiocarbamate), or alkylene bis(dialkyl-dithiocarbamate) and the like antiwear agents. The phosphorus containing antiwear agents are more fully described in European Patent 612 839. The metal in the dialkyl dithio phosphate salts may be an alkali metal, alkaline earth metal, aluminum, lead, tin, molybdenum, manganese, nickel, copper, titanium, or zinc. A useful antiwear agent may be zinc dialkyldithiophosphate.

[0068] Further examples of suitable antiwear agents include titanium compounds, tartrates, tartrimides, oil soluble amine salts of phosphorus compounds, sulfurized olefins, phosphites (such as dibutyl phosphite), phosphonates, thiocarbamate-containing compounds, such as thiocarbamate esters, thiocarbamate amides, thiocarbamic ethers, alkylene-coupled thiocarbamates, and bis(S-alkyldithiocarbamyl) disulfides. The tartrate or tartrimide may contain alkyl-ester groups, where the sum of carbon atoms on the alkyl groups may be at least 8. The antiwear agent may in one embodiment include a citrate.

[0069] The antiwear agent may be present in ranges including about 0 wt % to about 15 wt %, or about 0.01 wt % to about 10 wt %, or about 0.05 wt % to about 5 wt %, or about 0.1 wt % to about 3 wt % of the lubricating oil composition. In other embodiments, the compositions here may further include one or more oil-soluble molybdenum compounds, and if included, providing about 200 ppm or less of molybdenum, less than about 150 ppm, less than about 100 ppm, or less than about 50 ppm of molybdenum.

[0070] ANTIOXIDANTS: In some embodiments, the lubricating oil compositions herein may contain one or more antioxidants. Suitable antioxidants include phenolic antioxidants, aromatic amine antioxidants, sulfur containing antioxidants, and organic phosphites, among others.

[0071] Examples of phenolic antioxidants include 2,6-di-tert-butylphenol, liquid mixtures of tertiary butylated phenols, 2,6-di-tert-butyl-4-methylphenol, 4,4′-methylenebis(2,6-di-tert-butylphenol), 2,2′-methylenebis(4-methyl-6-ter-t-butylphenol), and mixed methylene-bridged polyalkyl phenols, and 4,4′-thiobis(2-methyl-6-tert-butylphenol), N,N′-di-sec-butyl-phenylenediamine, 4-iisopropylaminodiphenylamine, phenyl-alpha-naphthyl amine, phenyl-alpha-naphthyl amine, and ring-alkylated diphenylamines. Examples include the sterically hindered tertiary butylated phenols, bisphenols and cinnamic acid derivatives and combinations thereof.

[0072] Aromatic amine antioxidants include, but are not limited to diarylamines having the formula:wherein R′ and R″ each independently represents a substituted or unsubstituted aryl group having from 6 to 30 carbon atoms. Illustrative of substituents for the aryl group include aliphatic hydrocarbon groups such as alkyl having from 1 to 30 carbon atoms, hydroxy groups, halogen radicals, carboxylic acid or ester groups, or nitro groups.The aryl group is preferably substituted or unsubstituted phenyl or naphthyl, particularly wherein one or both of the aryl groups are substituted with at least one alkyl having from 4 to 30 carbon atoms, preferably from 4 to 18 carbon atoms, most preferably from 4 to 9 carbon atoms. It is preferred that one or both aryl groups be substituted, e.g. mono-alkylated diphenylamine, di-alkylated diphenylamine, or mixtures of mono- and di-alkylated diphenylamines.

[0074] Examples of diarylamines that may be used include, but are not limited to: diphenylamine; various alkylated diphenylamines, 3-hydroxydiphenylamine, N-phenyl-1,2-phenylenediamine, N-phenyl-1,4-phenylenediamine, monobutyldiphenyl-amine, dibutyl diphenylamine, monooctyldiphenylamine, dioctyldiphenylamine, monononyl diphenylamine, dinonyldiphenylamine, monotetradecyldiphenylamine, ditetradecyl diphenylamine, phenyl-alpha-naphthylamine, monooctyl phenyl-alpha-naphthylamine, phenyl-beta-naphthylamine, monoheptyldiphenylamine, diheptyl-diphenylamine, p-oriented styrenated diphenylamine, mixed butyloctyldi-phenylamine, and mixed octylstyryldiphenylamine.

[0075] The sulfur containing antioxidants include, but are not limited to, sulfurized olefins that are characterized by the type of olefin used in their production and the final sulfur content of the antioxidant. High molecular weight olefins, i.e., those olefins having an average molecular weight of 168 to 351 g / mole, are preferred. Examples of olefins that may be used include alpha-olefins, isomerized alpha-olefins, branched olefins, cyclic olefins, and combinations of these.

[0076] Alpha-olefins include, but are not limited to, any C4 to C25 alpha-olefins. Alpha-olefins may be isomerized before the sulfurization reaction or during the sulfurization reaction. Structural and / or conformational isomers of the alpha olefin that contain internal double bonds and / or branching may also be used. For example, isobutylene is a branched olefin counterpart of the alpha-olefin 1-butene.

[0077] Sulfur sources that may be used in the sulfurization reaction of olefins include: elemental sulfur, sulfur monochloride, sulfur dichloride, sodium sulfide, sodium polysulfide, and mixtures of these added together or at different stages of the sulfurization process.

[0078] Unsaturated oils, because of their unsaturation, may also be sulfurized and used as an antioxidant. Examples of oils or fats that may be used include corn oil, canola oil, cottonseed oil, grapeseed oil, olive oil, palm oil, peanut oil, coconut oil, rapeseed oil, safflower seed oil, sesame seed oil, soybean oil, sunflower seed oil, tallow, and combinations of these.

[0079] The total amount of antioxidant in the lubricating oil composition described herein may be present in an amount to deliver up to about 200 ppm nitrogen, or up to about 150 ppm nitrogen, or about 100 to about 150 ppm nitrogen.

[0080] FRICTION MODIFIERS: In some embodiments, the lubricating oil compositions herein may also contain additional friction modifiers other than those contained in the friction modifier system described above. Suitable additional friction modifiers may comprise metal containing and metal-free friction modifiers and may include, but are not limited to, imidazolines, amides, amines, succinimides, alkoxylated amines, alkoxylated ether amines, amine oxides, amidoamines, nitriles, betaines, quaternary amines, imines, amine salts, amino guanidine, alkanolamides, phosphonates, metal-containing compounds, glycerol esters, sulfurized fatty compounds and olefins, sunflower oil other naturally occurring plant or animal oils, dicarboxylic acid esters, esters or partial esters of a polyol and one or more aliphatic or aromatic carboxylic acids, and the like.

[0081] Suitable friction modifiers may contain hydrocarbyl groups that are selected from straight chain, branched chain, or aromatic hydrocarbyl groups or mixtures thereof, and such hydrocarbyl groups may be saturated or unsaturated. The hydrocarbyl groups may be composed of carbon and hydrogen or hetero atoms such as sulfur or oxygen. The hydrocarbyl groups may range from 12 to 25 carbon atoms. In some embodiments the friction modifier may be a long chain fatty acid ester. In another embodiment the long chain fatty acid ester may be a mono-ester, or a di-ester, or a (tri)glyceride. The friction modifier may be a long chain fatty amide, a long chain fatty ester, a long chain fatty epoxide derivative, or a long chain imidazoline.

[0082] Other suitable friction modifiers may include organic, ashless (metal-free), nitrogen-free organic friction modifiers. Such friction modifiers may include esters formed by reacting carboxylic acids and anhydrides with alkanols and generally include a polar terminal group (e.g. carboxyl or hydroxyl) covalently bonded to an oleophilic hydrocarbon chain. An example of an organic ashless nitrogen-free friction modifier is known generally as glycerol monooleate (GMO) which may contain mono-, di-, and tri-esters of oleic acid. Other suitable friction modifiers are described in U.S. Pat. No. 6,723,685.

[0083] Aminic friction modifiers may include amines or polyamines. Such compounds can have hydrocarbyl groups that are linear, either saturated or unsaturated, or a mixture thereof and may contain from 12 to 25 carbon atoms. Further examples of suitable friction modifiers include alkoxylated amines and alkoxylated ether amines. Such compounds may have hydrocarbyl groups that are linear, either saturated, unsaturated, or a mixture thereof. They may contain from about 12 to about 25 carbon atoms. Examples include ethoxylated amines and ethoxylated ether amines.

[0084] The amines and amides may be used as such or in the form of an adduct or reaction product with a boron compound such as a boric oxide, boron halide, metaborate, boric acid or a mono-, di- or tri-alkyl borate. Other suitable friction modifiers are described in U.S. Pat. No. 6,300,291.

[0085] If the additional friction modifiers contain nitrogen, such additional friction modifiers may be present in the lubricating oil composition in any amount as long as the performance requirements are not compromised.

[0086] CORROSION INHIBITORS: Other rust or corrosion inhibitors may also be included in the lubricating oil compositions described herein. Such materials include monocarboxylic acids and polycarboxylic acids. Examples of suitable monocarboxylic acids are octanoic acid, decanoic acid and dodecanoic acid. Suitable polycarboxylic acids include dimer and trimer acids such as are produced from such acids as tall oil fatty acids, oleic acid, linoleic acid, or the like.

[0087] Another useful type of rust inhibitor may be alkenyl succinic acid and alkenyl succinic anhydride corrosion inhibitors such as, for example, tetrapropenylsuccinic acid, tetrapropenylsuccinic anhydride, tetradecenylsuccinic acid, tetradecenylsuccinic anhydride, hexadecenylsuccinic acid, hexadecenylsuccinic anhydride, and the like. Also useful are the half esters of alkenyl succinic acids having 8 to 24 carbon atoms in the alkenyl group with alcohols such as the polyglycols. Other suitable rust or corrosion inhibitors include ether amines, acid phosphates, amines, polyethoxylated compounds such as ethoxylated amines, ethoxylated phenols, and ethoxylated alcohols, imidazolines, aminosuccinic acids or derivatives thereof, and the like. Mixtures of such rust or corrosion inhibitors may be used. The total amount of corrosion inhibitor, when present in the lubricating composition described herein may range up to 2.0 wt % or from 0.01 to 1.0 wt % based on the total weight of the lubricating composition.

[0088] DEMULSIFIERS: Demulsifiers may also be included in the compositions herein and may include trialkyl phosphates, and various polymers and copolymers of ethylene glycol, ethylene oxide, propylene oxide, or mixtures thereof, including polyethylene oxides, polypropylene oxides and (ethylene oxide-propylene oxide) polymers. When present, the amount of demulsifier in the lubricating oil composition may be up about 0.05 wt, or up to about 0.02 wt %, or below about 0.015 wt % based on the total weight of the lubricating oil composition.

[0089] ANTIFOAM AGENTS: Antifoam agents used to reduce or prevent the formation of stable foam include silicones, polyacrylates, or organic polymers. Foam inhibitors that may be useful in the compositions of the disclosed invention include polysiloxanes, copolymers of ethyl acrylate and 2-ethylhexylacrylate and optionally vinyl acetate. When present, the amount of antifoam in the lubricating oil composition may be up about 0.1 wt, or up to about 0.05 wt %, or below about 0.04 wt % based on the total weight of the lubricating oil composition.

[0090] POUR POINT DEPRESSANTS: The lubricating oil compositions herein may optionally contain one or more pour point depressants. Suitable pour point depressants may include esters of maleic anhydride-styrene, polymethacrylates, polymethylmethacrylates, polyacrylates or polyacrylamides or mixtures thereof. Pour point depressants, when present, may be present in amount from about 0.001 wt % to about 0.04 wt %, based upon the total weight of the lubricant.

[0091] In general terms, a lubricating oil composition described herein may include additive components in the ranges listed in Table 2.TABLE 2Wt. %Wt. %(Suitable(PreferredComponentEmbodiments)Embodiments)Detergent Systems1.0-5.01.0-3.0Viscosity Modifier OCP 0.5-2.00.7-1.8(active Polymer)Dispersant Systems 2.0-15.0 4.0-10.0Antioxidant(s)1.0-5.01.0-3.0Ashless TBN booster(s)0.0-1.00.01-0.5 Corrosion inhibitor(s)0.0-5.00.0 -2.0 Metal dihydrocarbyldi-0.0-6.00.5-2.0thiophosphate(s)Ash-free phosphorus0.0-6.00.0-4.0compound(s)Antifoaming agent(s)0.0-1.00.001-0.15 Other Antiwear agent(s)0.0-1.00.0-0.8Pour point0.0-1.00.00-0.5 depressant(s)Viscosity index 0.0-15.0 1.0-10.0improver(s)Friction modifier(s)0.00-1.0 0.01-0.8 Base oilBalanceBalanceTotal100100

[0092] The percentages of each component above represent the weight percent of each component, based upon the total weight of the lubricating oil composition containing the recited component. Additives used in formulating the compositions described herein may be blended into the base oil individually or in various sub-combinations. However, it may be suitable to blend all of the components concurrently using an additive concentrate (i.e., additives plus a diluent, such as a hydrocarbon solvent). The use of an additive concentrate takes advantage of the mutual compatibility afforded by the combination of ingredients when in the form of an additive concentrate. Also, the use of a concentrate reduces blending time and lessens the possibility of blending errors.

[0093] Unless the context of discussion herein suggests otherwise, the following definitions of terms are provided in order to clarify the meanings of certain terms as used herein.

[0094] The terms “lubricating oil,”“lubricant composition,”“lubricating composition,”“lubricant” and “lubricating oil composition” refer to a finished lubrication product comprising a major amount of a base oil plus a minor amount of an additive composition. As used herein, a major amount includes at least 50 weight percent or more and a minor amount includes less than 50 weight percent.

[0095] As used herein, the terms “additive package,”“additive concentrate,” and “additive composition,” refer the portion of the lubricating oil composition excluding the major amount of base oil.

[0096] As used herein, the term “hydrocarbyl substituent” or “hydrocarbyl group” is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having a predominantly hydrocarbon character. Each hydrocarbyl group is independently selected from hydrocarbon substituents, and substituted hydrocarbon substituents containing one or more of halo groups, hydroxyl groups, alkoxy groups, mercapto groups, nitro groups, nitroso groups, amino groups, pyridyl groups, furyl groups, imidazolyl groups, oxygen and nitrogen, and wherein no more than two non-hydrocarbon substituents are present for every ten carbon atoms in the hydrocarbyl group.

[0097] As used herein, the term “percent by weight” or “wt %”, unless expressly stated otherwise, means the percentage the recited component represents to the weight of the entire composition.

[0098] The terms “soluble,”“oil-soluble,” or “dispersible” used herein may, but does not necessarily, indicate that the compounds or additives are soluble, dissolvable, miscible, or capable of being suspended in the oil in all proportions. The foregoing terms do mean, however, that they are, for instance, soluble, suspendable, dissolvable, or stably dispersible in oil to an extent sufficient to exert their intended effect in the environment in which the oil is employed. Moreover, the additional incorporation of other additives may also permit incorporation of higher levels of a particular additive, if desired.

[0099] The term “alkyl” as employed herein refers to straight, branched, cyclic, and / or substituted saturated chain moieties from about 1 to about 200 carbon atoms.

[0100] The term “alkenyl” as employed herein refers to straight, branched, cyclic, and / or substituted unsaturated chain moieties from about 3 to about 30 carbon atoms.

[0101] The term “aryl” as employed herein refers to single and multi-ring aromatic compounds that may include alkyl, alkenyl, alkylaryl, amino, hydroxyl, alkoxy, halo substituents, and / or heteroatoms including, but not limited to, nitrogen, and oxygen.

[0102] As used herein, the “average number molecular weight” or “Mn” is determined by gel permeation chromatography (GPC) using commercially available polystyrene standards (with a Mn of about 180 to about 18,000 as the calibration reference).

[0103] It is to be understood that throughout the present disclosure, the terms “comprises,”“includes,”“contains,” etc. are considered open-ended and include any element, step, or ingredient not explicitly listed. The phrase “consists essentially of” is meant to include any expressly listed element, step, or ingredient and any additional elements, steps, or ingredients that do not materially affect the basic and novel aspects of the invention. The present disclosure also contemplates that any composition described using the terms, “comprises,”“includes,”“contains,” is also to be interpreted as including a disclosure of the same composition “consisting essentially of” or “consisting of” the specifically listed components thereof.Examples

[0104] A better understanding of the present disclosure and its many advantages may be clarified with the following examples. The following examples are illustrative and not limiting thereof in either scope or spirit. Those skilled in the art will readily understand that variations of the components, methods, steps, and devices described in these examples can be used. Unless noted otherwise or apparent from the context of discussion in the Example below and throughout this disclosure and claims, all percentages, ratios, and parts noted in this disclosure are by weight. Any standardized test method noted in the Examples, disclosure, or claims, unless apparent from the context of its use, refers to the version of the test method publicly available at the time of the filing of the present disclosure.Example 1

[0105] This Examples evaluated stochastic pre-ignition (SPI) per 1000 cycles using hydrogen-fueled internal combustion engines at the Graz University of Technology (Austria). SPI was evaluated using a test method developed at the Graz University of Technology using a 4 cylinder 2.0 liter turbocharged and direct-injection passenger car engine converted to run on hydrogen fuel. The engine had a compression ratio of 9.8 and the turbocharger utilized variable turbine geometry.

[0106] The evaluation of SPI involved dosing a small defined quantity of the lubricant (e.g., about 0.6 grams per kilowatt-hours) was introduced as aerosolized drops into the intake area of one individual cylinder using an external dosing system and a dosing lance. The result for each test lubricant was derived from the number of pre-ignition events at the relevant cylinder during the dosing phase, while the other cylinders act as statistical reference.

[0107] The oil dosing was carried out at a steady-state operating point over a one-hour test program based on the dosing release over time. The test program included a 45 minutes pre-heat-up phase and then an evaluation divided into five 12 minute phases: (1) a 12-minute pre-conditioning phase, (2) a 12-minute oil first dosing phase, (3) a 12-minute mid-conditioning phase, (4) a 12-minute second dosing phase, and (5) a final 12-minute post-conditioning phase. At the end of each test, the external oil dosing unit was cleaned and prepared for the next test. The tests were performed at an operating point of about 1350 rpm (rotations per minute) and a Brake mean effective pressure (BMEP) of about 17 bar. For purposes of this evaluation, an SPI event occurred if (i) the peak pressure in the dosing cylinder was 3 standard deviations or above the average peak pressure in the other cylinders and (ii) the crank angle degree of the dosing cylinder at 5 percent mass fraction of fuel burned (MFB05%) was also 3 standard deviations or below the other cylinders.

[0108] SPI in a hydrogen-fueled engine was evaluated using the lubricants of Table 3 below. All lubricants contained the same base additive package containing the same amount and type of dispersant, antioxidant, antifoam agent, pour point depressant, and friction modifier. All lubricants also included in the additive package an overbased magnesium sulfonate detergent having a TBN of about 400 (as measured by ASTM D2896) and providing about 2800 ppm magnesium to each lubricants (e.g., about 11.8 mmol of magnesium). Only the base oil type and the viscosity modifier copolymer were varied among the lubricants as shown in Tables 3 and 4 below. The viscosity modifier olefin copolymers used in this Example were as follows:

[0109] OCP 1: an ethylene propylene copolymer having approximately 49 weight percent ethylene monomer content, a weight average molecular weight of about 150,000 to about 160,000, a polydispersity index of about 1.5 to about 2.0, and had about 12.5 weight percent active copolymer in an API Group II diluent. OCP1 has a shear stability index (ASTM D6278) of 22.

[0110] OCP 2: an ethylene propylene copolymer having approximately 49 weight percent ethylene monomer content, a weight average molecular weight of about 270,000 to about 290,000, a polydispersity index of about 2.0 to about 2.5, and had about 7.5 weight percent active copolymer in an API Group II diluent. OCP2 has a shear stability index (ASTM D6278) of 50.TABLE 3LubricantsFluid 1Fluid 2Fluid 3Fluid 4Fluid 5Fluid 6Fluid 7Fluid 8OCP 1, active wt %—0.751.75——0.750.750.75OCP 2, active wt %———0.75————API GIII, wt %89.9583.9575.9579.95———42.0API GII, wt %—————83.95—42.0API GI, wt %————89.95—83.95—Mg Sulfonate, ppm Mg28002800280028002800280028002800Mmol Mg per 100 grams of lubricant11.811.811.811.811.811.811.811.8KV100, cSt11.477.8313.3710.086.829.4610.68.6HTHS150, cSt1.882.533.672.962.372.933.232.74NOACK, %12.412.517.21415.3—SPI / 1000 cycles208.9169.248.539.820.7463.5816.9144.44

[0111] As shown in Table 3 above, Fluid 1 includes an API group GIII base oil without an olefin copolymer and demonstrated high SPI in a hydrogen-fueled gas engine. Fluids 2 and 4 added 0.75 active weight percent of a low molecular weight olefin copolymer and a high molecular weight olefin copolymer (respectively), and both fluids demonstrated an improvement in SPI. As shown in Fluid 3, the addition of 1.75 active weight percent of the low molecular weight olefin copolymer provided even additional improvement in SPI as compared to Fluid 2. Fluids 5, 6, and 7 used lower quality base oils from API Group I or Group II. It was unexpected that the API Group I and II base oils, which are widely accepted as lower quality base oils, achieved improved SPI especially without an olefin copolymer (e.g., Fluid 5) and / or when combined with the selected olefin copolymer and / or at least about 1000 ppm of magnesium (e.g., Fluids 6 and 7). While Fluid 3 with API Group III base oils improved SPI, Fluid 8 that replaced some of the Group III base oil with a lower quality Group II base oil unexpectedly achieved an even lower SPI when combined with the lower molecular weight olefin copolymer.

[0112] It is to be understood that while the lubricating composition and compositions of this disclosure have been described in conjunction with the detailed description thereof and summary herein, the foregoing description is intended to illustrate and not limit the scope of the disclosure, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the claims. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims.

[0113] Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein. As used throughout the specification and claims, “a” and / or “an” may refer to one or more than one. Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, percent, ratio, reaction conditions, and so forth used in the specification are to be understood as being modified in all instances by the term “about,” whether or not the term “about” is present. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification are approximations that may vary depending upon the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0114] It is to be understood that each component, compound, substituent or parameter disclosed herein is to be interpreted as being disclosed for use alone or in combination with one or more of each and every other component, compound, substituent or parameter disclosed herein.

[0115] It is further understood that each range disclosed herein is to be interpreted as a disclosure of each specific value within the disclosed range that has the same number of significant digits. Thus, a range of from 1 to 4 is to be interpreted as an express disclosure of the values 1, 2, 3 and 4 as well as any range of such values such as 1 to 4, 1 to 3, 1 to 2, 2 to 4, 2 to 3 and so forth.

[0116] It is further understood that each lower limit of each range disclosed herein is to be interpreted as disclosed in combination with each upper limit of each range and each specific value within each range disclosed herein for the same component, compounds, substituent or parameter. Thus, this disclosure to be interpreted as a disclosure of all ranges derived by combining each lower limit of each range with each upper limit of each range or with each specific value within each range, or by combining each upper limit of each range with each specific value within each range.

[0117] Furthermore, specific amounts / values of a component, compound, substituent or parameter disclosed in the description or an example is to be interpreted as a disclosure of either a lower or an upper limit of a range and thus can be combined with any other lower or upper limit of a range or specific amount / value for the same component, compound, substituent or parameter disclosed elsewhere in the application to form a range for that component, compound, substituent or parameter.

Examples

example 1

[0105]This Examples evaluated stochastic pre-ignition (SPI) per 1000 cycles using hydrogen-fueled internal combustion engines at the Graz University of Technology (Austria). SPI was evaluated using a test method developed at the Graz University of Technology using a 4 cylinder 2.0 liter turbocharged and direct-injection passenger car engine converted to run on hydrogen fuel. The engine had a compression ratio of 9.8 and the turbocharger utilized variable turbine geometry.

[0106]The evaluation of SPI involved dosing a small defined quantity of the lubricant (e.g., about 0.6 grams per kilowatt-hours) was introduced as aerosolized drops into the intake area of one individual cylinder using an external dosing system and a dosing lance. The result for each test lubricant was derived from the number of pre-ignition events at the relevant cylinder during the dosing phase, while the other cylinders act as statistical reference.

[0107]The oil dosing was carried out at a steady-state operating ...

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application is a continuation-in-part of U.S. patent application Ser. No. 18 / 931,962, filed on Oct. 30, 2024, which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure relates to lubricating fluids for internal combustion engines fueled with alternative combustion fuels having high auto-ignition temperatures, as well as methods of lubricating an internal combustion engine using the lubricating fluids when fueled with such alternative combustion fuels.BACKGROUND

[0003] Automotive and powertrain manufacturers are investigating alternative combustion fuels as substitutes for conventional gasoline and diesel fuels. These alternative fuels are characterized by elevated auto-ignition temperatures, typically at or above approximately 700K, and include hydrogen, compressed natural gas (CNG), and liquefied natural gas (LNG). Engines powered by hydrogen or natural gas offer several benefits. Notably, conventional internal combustion engines can typically operate on these fuels with minimal or no modifications. This compatibility facilitates adoption by leveraging established, reliable, and characterized engine architectures that have been refined over an extended period.

[0004] A significant technical challenge associated with hydrogen-fueled and natural gas-fueled engines, however, involves a phenomenon known as stochastic pre-ignition (SPI). This phenomenon represents a primary obstacle to the broader commercialization of internal combustion engines utilizing hydrogen or natural gas as fuel. SPI refers to an unintended premature combustion event of the primary fuel charge, which results in early detonation, misfiring, and engine knock. While SPI shares similarities with low-speed pre-ignition (LSPI), a condition commonly observed in turbocharged gasoline engines employing direct injection, established mitigation strategies effective against LSPI in conventional gasoline powertrains do not reliably address SPI in hydrogen or natural gas applications.

[0005] Previously it was believed that API Group III base oils combined with polymethacrylate (PMA) copolymers aided in the reduction of SPI in hydrogen fueled engines. According to US 2025 / 0263625, in a study that evaluated uncontrolled ignition in hydrogen engines at the Graz University of Technology, API Group II base oils performed worse in the context of SPI and API GIII base oils performed better. As explained in the evaluation of the '625 patent, the baseline lubricant with an API Group II base oil and olefin copolymer (e.g., Paratone 24EX that is believed to have 60 weight percent ethylene content, a weight average molecular weight of about 168,000 g / mol, and a polydispersity index of about 2.1) had very poor relative performance in total pre-ignition events in hydrogen fueled engines as compared to lubricants with API Group III base oils and / or lubricants with polymethacrylate (PMA) copolymers.SUMMARY

[0006] In one embodiment, a lubricating oil composition configured for lubricating an internal combustion engine fueled with a fuel having an auto-ignition temperature greater than about 700K is described. In one aspect, the lubricating oil composition included one or more base oils of lubricating viscosity; a viscosity modifier olefin copolymer having a weight average molecular weight of about 100,000 to about 200,000 g / mol and about 55 mol percent or less of ethylene monomer content; and wherein the lubricating oil composition includes at least about 0.8 weight percent based on active copolymer content, of the viscosity modifier olefin copolymer.

[0007] In other embodiments, the lubricating oil composition of the previous paragraph may include other features or embodiments in any combination. These other features or embodiment include one or more of the following: wherein the one or more base oils of lubricating viscosity includes one or more API Group III base oils; and / or wherein the viscosity modifier olefin copolymer has a weight average molecular weight of about 170,000 to about 200,000 g / mol; wherein lubricating oil composition further includes an overbased magnesium-containing metal detergent having a TBN of at least about 200 mg KOH / g (ASTM D2896) and providing about 1000 to about 3000 ppm of magnesium to the lubricating oil composition; and / or wherein the olefin copolymer includes about 45 to about 55 mol percent of ethylene monomer content and about 45 to about 55 mol percent of propylene monomer content; and / or wherein the lubricating oil composition includes about 0.8 weight percent to about 2 weight percent, based on active copolymer content, of the viscosity modifier olefin copolymer; and / or wherein the viscosity modifier olefin copolymer is diluted in an API Group I and / or Group II base oil, and wherein the viscosity modifier olefin copolymer is about 5 to about 15 weight percent of active copolymer in the API Group I and / or Group II base oil; and / or wherein the viscosity modifier olefin copolymer has a shear stability index as measured pursuant to ASTM D6278 of 18 to 26; and / or wherein the lubricating oil composition is substantially free of poly(meth)acrylate copolymers; and / or wherein the fuel having an auto-ignition temperature greater than about 700K is hydrogen fuel; and / or wherein the lubricating oil composition has an average measured stochastic pre-ignition (SPI) of about 50 SPI counts or less per 1000 cycles at 1350 rpm and 17 bar brake mean effective pressure (BMEP) when evaluated as described in the Examples; and / or wherein the lubricating oil composition has a KV100 of 13.5 cSt or less.

[0008] In another embodiment, a method of lubricating an internal combustion engine when fueled with a fuel having an auto-ignition temperature greater than about 700K to mitigate abnormal combustion events is described herein. In an aspect, the method includes lubricating a crankcase of an internal combustion engine with a lubricating oil composition and combusting a fuel having an auto-ignition temperature greater than about 700K in the internal combustion engine; and wherein the lubricating oil composition includes any embodiment of the lubricating composition as described in the previous two paragraphs.

[0009] In a further embodiment, a lubricating oil composition configured for lubricating an internal combustion engine fueled with a fuel having an auto-ignition temperature greater than about 700K is described herein wherein the lubricating oil composition includes one or more base oils of lubricating viscosity, wherein the one or more base oils include one or more API Group I base oils, one or more API Group II base oils, or combinations thereof, and an overbased magnesium-containing metal detergent having a TBN of at least about 200 mg KOH / g (ASTM D2896) and providing about 1000 to about 3000 ppm of magnesium to the lubricating oil composition.

[0010] In yet further embodiments, the lubricating oil composition of the previous paragraph may include other features or embodiments in any combination. These other features and embodiment include one or more of the following: wherein the lubricating oil composition includes at least about 0.7 weight percent, based on active content, of a viscosity modifier olefin copolymer having a weight average molecular weight of up to about 200,000 g / mol and about 55 mol percent or less of ethylene monomer content; and / or wherein the viscosity modifier olefin copolymer has a weight average molecular weight about 170,000 to about 200,000 g / mol; and / or wherein the wherein the lubricating oil composition has a KV100 of 11 cSt or less; and / or wherein the viscosity modifier olefin copolymer includes about 45 to about 55 mol percent of ethylene monomer content and about 45 to about 55 mol percent of propylene monomer content; and / or wherein the wherein the lubricating oil composition includes about 0.6 weight percent to about 2 weight percent, based on active copolymer content, of the viscosity modifier olefin copolymer; and / or wherein the viscosity modifier olefin copolymer is diluted in an API Group I and / or Group II base oil, and wherein the viscosity modifier olefin copolymer is about 5 to about 15 weight percent of active copolymer content in the API Group I or Group II base oil; and / or wherein the viscosity modifier olefin copolymer has a shear stability index as measured pursuant to ASTM D6278 of 18 to 26; and / or wherein the lubricating oil composition is substantially free of poly(meth)acrylate copolymers; and / or wherein the fuel having an auto-ignition temperature greater than about 700K is hydrogen fuel; and / or wherein the lubricating oil composition has an average measured stochastic pre-ignition (SPI) of about 65 SPI counts or less per 1000 cycles at 1350 rpm and 17 bar brake mean effective pressure (BMEP).

[0011] In yet another embodiment, a method of lubricating an internal combustion engine when fueled with a fuel having an auto-ignition temperature greater than about 700K to mitigate abnormal combustion events is also described herein wherein the method includes lubricating a crankcase of an internal combustion engine with a lubricating oil composition and combusting a fuel having an auto-ignition temperature greater than about 700K in the internal combustion engine; and wherein the lubricating oil composition includes a composition of any embodiment described in the previous two paragraphs.

[0012] In a further embodiment, a lubricating oil composition configured for lubricating an internal combustion engine fueled with a fuel having an auto-ignition temperature greater than about 700K is described herein wherein the lubricating oil composition includes one or more base oils of lubricating viscosity; and a viscosity modifier olefin copolymer having a weight average molecular weight of about 200,000 to about 500,000 g / mol, about 55 mol percent or less of ethylene monomer content, and a shear stability index as measured pursuant to ASTM D6278 of 50 to 55.

[0013] In yet other embodiments, the lubricating oil composition of the previous paragraph may include other features or embodiments in any combination. These other features or embodiment include one or more of the following: wherein the one or more base oils of lubricating viscosity includes one or more API Group I base oils, one or more API Group II base oils, one or more API Group III base oils, or combinations thereof, and / or wherein lubricating oil composition further includes an overbased magnesium-containing metal detergent having a TBN of at least about 200 (ASTM D2896) and providing about 1000 to about 3000 ppm of magnesium to the lubricating oil composition; and / or wherein the viscosity modifier olefin copolymer includes about 45 to about 55 mol percent of ethylene monomer content and about 45 to about 55 mol percent of propylene monomer content; and / or wherein the wherein the lubricating oil composition includes about 0.6 weight percent to about 2 weight percent, based on active copolymer content, of the viscosity modifier olefin copolymer; and / or wherein the viscosity modifier olefin copolymer is diluted in an API Group I and / or Group II base oil, and wherein the olefin copolymer is about 5 to about 15 weight percent of active copolymer content in the API Group I or Group II base oil; and / or wherein the lubricating oil composition is substantially free of poly(meth)acrylate copolymers; and / or wherein the fuel having an auto-ignition temperature greater than about 700K is hydrogen fuel; and / or wherein the lubricating oil composition has an average measured stochastic pre-ignition (SPI) of about 50 SPI counts or less per 1000 cycles at 1350 rpm and 17 bar brake mean effective pressure (BMEP) as described in the Examples.

[0014] In yet another embodiment, a method of lubricating an internal combustion engine when fueled with a fuel having an auto-ignition temperature greater than about 700K to mitigate abnormal combustion events is described herein and wherein the method includes lubricating a crankcase of an internal combustion engine with a lubricating oil composition and combusting a fuel having an auto-ignition temperature greater than about 700K in the internal combustion engine; and wherein the lubricating oil composition includes any embodiment as described in the previous two paragraphs.

[0015] In another embodiment, the use of any embodiment of the lubricating compositions as described in this Summary is also provided herein for achieving an average measured stochastic pre-ignition (SPI) of about 65 SPI counts or less or, in other embodiments, about 50 SPI counts or less per 1000 cycles at 1350 rpm and 17 bar brake mean effective pressure (BMEP) when evaluated as described in the Examples herein.

[0016] Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein.DETAILED DESCRIPTION

[0017] Stochastic pre-ignition (SPI) is a limiting factor in widespread use of alternative combustion fuels (as considered herein, fuels having an auto-ignition temperature of at least about 700K) in internal combustion engines. While SPI is a phenomenon that tends to be similar to low speed pre-ignition (LSPI) in gasoline engines that is sometimes confronted in certain turbocharged direct-injection engine gasoline engines, solutions to address LSPI in gasoline engines do not necessarily improve SPI in, for instance, hydrogen-fueled or natural gas-fueled internal combustion engines. Thus, conventional gasoline engine lubricants cannot necessarily be used in engines operated with the alternative combustion fuels, such as hydrogen-fueled engines or natural gas-fueled internal combustion engines.

[0018] According to exemplary embodiments, lubricating oil compositions are provided herein that are configured for use in or for methods of lubricating an internal combustion engine fueled with an alternative fuel having an auto-ignition temperature of at least about 700K (preferably, fuels having an auto-ignition temperature of 850K or above, and most preferably, hydrogen fuel). The lubricating oil compositions herein are effective to reduce SPI in engines fueled with such alternative fuels.

[0019] In one approach or embodiment, the lubricating oil compositions include one or more base oils of lubricating viscosity and a lower molecular weight viscosity modifier olefin copolymer. In one aspect, the lower molecular weight viscosity modifier olefin copolymer has a weight average molecular weight of up to about 200,000 g / mol (in other approaches, about 100,000 to about 200,000 g / mol) and includes about 55 mol percent or less of ethylene monomer content (in other embodiments, about 45 to about 55 mol percent, or about 48 to about 51 mol percent of ethylene monomer content). As shown in the Examples below, the use of such lower molecular weight viscosity modifier olefin copolymer, when the polymer used is of the molecular weight and / or percent ethylene monomer content specified, aids in the reduction of SPI. In other aspects, the lubricating oil compositions include at least about 0.8 weight percent, based on active copolymer content, of such lower molecular weight viscosity modifier olefin copolymer. As demonstrated in the Examples, this discovered amount, in some embodiments, may aid in reducing SPI. In other approaches of this embodiment, the one or more base oils of lubricating viscosity is one or more API Group III base oils.

[0020] In a second approach or embodiment, the lubricating oil compositions include base oils of lubricating viscosity selected from one or more API Group I base oils, one or more API Group II base oils, or combinations thereof that are widely accepted as lower quality base oils. The compositions of this second approach combine such lower quality base oils with an overbased magnesium-containing metal detergent (e.g., an overbased magnesium sulfonate detergent) having a TBN of at least about 200 mg KOH / g (ASTM D2896) and that provides about 4 to about 12 mmol of magnesium per 100 grams of the lubricating oil composition. In other approaches, the overbased magnesium-containing metal detergent provides at least about 1000 ppm of magnesium to the compositions (in other embodiments, about 1000 ppm to about 3000 ppm of magnesium or about 2000 ppm to about 3000 ppm of magnesium). This second embodiment may also include amounts of the lower molecular weight viscosity modifier olefin copolymer and, if included, the lubricating oil composition may include at least about 0.7 weight percent, based on active content, of the lower molecular weight viscosity modifier olefin copolymer having a weight average molecular weight of up to about 200,000 g / mol (in other approaches, about 100,000 to about 200,000 g / mol) and with about 55 mol percent or less of ethylene monomer content (in other embodiments, about 45 to about 55 mol percent, or about 48 to about 51 mol percent of ethylene monomer content). As shown in the Examples, the use of such amounts of the magnesium-containing detergent and the lower molecular weight viscosity modifier olefin copolymer aids in the reduction of SPI when combined with the lower quality API Group I and / or Group II base oils.

[0021] In a third approach or embodiment, the lubricating oil compositions include one or more base oils of lubricating viscosity and a viscosity modifier olefin copolymer having a higher molecular weight and, in this embodiment, the higher molecular weight viscosity modifier olefin copolymer has a weight average molecular weight greater than about 200,000 g / mol or, in other embodiments, greater than about 200,000 g / mol to about 500,000 g / mol, and in yet further embodiments, about 250,000 g / mol to about 350,000 g / mol. As shown in the Examples, the use of this higher molecular weight viscosity modifier olefin copolymer, when the polymer used is of the higher molecular weight, includes a certain percent ethylene monomer content, and / or specific shear stability index, may also aid in the reduction of SPI. Further, the higher molecular weight viscosity modifier olefin copolymer used in this embodiment, in addition to having the higher molecular weight, may also have a shear stability index, as measured pursuant to ASTM D6278, of 50 to 55. In other embodiments, the higher molecular weight viscosity modifier olefin copolymer may be diluted in about 85 to about 95 weight percent of an API Group I and / or Group II base oil.Viscosity Modifier

[0022] Embodiments of the lubricating oil compositions herein may include a viscosity modifier. The viscosity modifier is preferably an olefin copolymer having a certain molecular weight, ethylene monomer content, and / or shear stability index. The compositions herein are also preferably substantially free of poly(meth)acrylate (PMA) viscosity modifier polymers (in this context, substantially free means less than about 0.5 weight percent, less than about 0.1 weight percent, less than 0.05, or no detectable levels of PMA viscosity modifier polymers based on active PMA content). The term “olefin copolymer” or “OCP” as used herein refers to a polymer formed by copolymerizing two or more olefin monomers (e.g., ethylene and propylene) to create polymers with specific molecular weight distributions and compositions that modify the viscosity-temperature behavior of lubricating oils. The properties of the olefin copolymer used are characterized in part by the molecular weight of the polymer, the monomer content used (at least the ethylene monomer content), and in some instances, a shear stability index (e.g., SSI as measured pursuant to ASTM D6278). The ethylene monomer content of the olefin copolymers is one metric impacting performance, where the amount of ethylene balances the solubility in the base oils used, the thickening efficiency of the polymer, and the shear stability (for example, according to ASTM D6278). These are characteristics of the polymer that aid in balancing the lubrication properties of the resulting lubricating composition that unexpectedly helps mitigate SPI when used in lubricants for the alternative fueled engines as described herein. The polydispersity index (PDI) is another property that may be considered, where PDI is defined as the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn). A PDI of 1.0 represents a monodisperse polymer, while values above 1.0 indicate greater distribution of chain length. PDI may be determined by techniques such as gel permeation chromatography.

[0023] In one embodiment, the compositions herein utilize a lower molecular weight viscosity modifier olefin copolymer having a weight average molecular weight of up to about 200,000 g / mol. For example, the lower molecular weight viscosity modifier olefin copolymer may have a weight average molecular weight of about 100,000 to about 200,000 g / mol, preferably 125,000 to 175,000 g / mol, or more preferably 150,000 to 160,000 g / mol. The ethylene monomer content of this lower molecular weight copolymer is about 55 mol percent or less of ethylene monomer content. In some embodiments, the olefin copolymers herein include about 45 to about 55 mol percent of ethylene monomer content (or about 48 to about 51 mol percent of ethylene monomer content). Preferably, the remainder of the monomer content includes propylene monomers; for example, about 45 to about 55 mol percent of propylene monomer content based on the total copolymer. The lower molecular weight olefin copolymer of this aspect has a polydispersity index of over 1.2, preferably greater than 1.5. For example, the PDI may be 1.5 to 2.0. In yet other embodiments, this lower molecular weight olefin copolymer has a shear stability index SSI as measured pursuant to ASTM D6278 of about 18 to about 26 or, preferably about 20 to about 24. The lower molecular weight olefin copolymer may be diluted, in some embodiments, in about 85 to about 95 weight percent of an API Group I and / or Group II base oil.

[0024] In one embodiment, suitable amounts of the lower molecular weight viscosity modifier olefin copolymer used in the lubricating oil composition is at least about 0.8 weight percent, based on active copolymer content, of the viscosity modifier olefin copolymer. In other embodiments, the lower molecular weight viscosity modifier olefin copolymer is used in amounts of at least about 1.0 weight percent, or in other embodiments, about 0.8 weight percent to about 2 weight percent based on active polymer content, and more preferably about 1.5 to about 2.0 weight percent based on active polymer content. Preferably, such amounts of the lower molecular weight viscosity modifier olefin copolymer are suitable for use with an API Group III base oil.

[0025] In an alternative embodiment, the lubricating oil composition includes at least about 0.7 weight percent, based on active copolymer content, of the lower molecular weight viscosity modifier olefin copolymer. For instance, the lubricating oil compositions herein may include at least about 0.7 weight percent of such olefin copolymer having a weight average molecular weight of up to about 200,000 g / mol and about 55 mol percent or less of ethylene monomer content (in other approaches, about 45 to about 55 mol percent of ethylene monomer content, or about 48 to about 51 mol percent of ethylene monomer conent). Preferably, such amounts of the lower molecular weight copolymer are most suitable for use with an API Group I or Group II base oil and when preferably combined with select amounts of magnesium from detergents (as discussed more below). In other embodiments, the lower molecular weight viscosity modifier olefin copolymer is used in amounts of about 0.7 weight percent to about 2 weight percent based on active polymer content, and more preferably about 0.7 to about 1.5 weight percent based on active polymer content along with the API Group I and / or Group II base oils.

[0026] In a further embodiment, the lower molecular weight viscosity modifier olefin copolymer is provided in the lubricating oil composition along with a diluent. In various embodiments, the diluent is an API Group I and / or Group II base oil. In embodiments, the lower molecular weight viscosity modifier olefin copolymer described herein may be about 5 to about 15 weight percent of the active copolymer content in the API Group I and / or Group II base oil as diluent. In a further embodiment, the lower molecular weight viscosity modifier olefin copolymer, when diluted in the API Group I and / or Group II base oil, has a shear stability index as measured pursuant to ASTM D6278 of 18 to 26 (or 20 to 24).

[0027] In another embodiment, a higher molecular weight viscosity modifier olefin copolymer may be used in the lubricating compositions of the present disclosure. In an aspect, the higher molecular weight viscosity modifier olefin copolymer has a weight average molecular weight of greater than 200,000 g / mol or greater than about 200,000 to about 500,000 g / mol. For example, a weight average molecular weight of about 250,000 to about 350,000 g / mol, preferably 270,000 to 290,000 g / mol. The ethylene monomer content of this higher molecular weight olefin copolymer is about 55 mol percent or less of ethylene monomer content. In some embodiments, this higher molecular weight olefin copolymer includes about 45 to about 55 mol percent of ethylene monomer content (or about 48 to about 51 mol percent). Preferably, the remainder of the monomer content of the higher molecular weight copolymer includes a propylene monomer; for example, about 45 to about 55 mol percent of propylene monomer content based on the total copolymer. The higher molecular weight olefin copolymer may also have a polydispersity index of over 1.2, preferably greater than 1.5. For example, the PDI may be about 1.8 to about 2.2 or about 2.0 to about 2.5. In yet other embodiments, the higher molecular weight olefin copolymers have a shear stability index SSI as measured pursuant to ASTM D6278 of about 50 to about 55 or, preferably about 51 to about 54. In embodiment, the higher molecular weight olefin copolymers may also be diluted in about 85 to about 95 weight percent of an API Group I and / or Group II base oil.

[0028] The amount of the higher molecular weight olefin copolymer, when used in the lubricating oil compositions herein, is preferably at least about 0.4 weight percent, based on active copolymer content. In further embodiments, the higher molecular weight olefin copolymer is used in the lubricating compositions in amounts, based on active polymer content, of greater than about 0.6 weight percent, and preferably about 0.4 to about 2.0 weight percent or more preferably about 0.6 to about 2.0 weight percent based on active copolymer content in the compositions and, most preferably, about 0.6 to about 1.0 weight percent based on active copolymer content. This higher molecular weight olefin copolymer may be used with an API Group I, Group II, and / or Group III base oil.

[0029] In a further embodiment, the higher molecular wight viscosity modifier olefin copolymer may also be provided along with a diluent. In various embodiments, the diluent suitable for the higher molecular weight viscosity modifier olefin copolymer is also an API Group I and / or Group II base oil. In further embodiments, the higher molecular weight viscosity modifier olefin copolymer is about 5 to about 15 weight percent of active copolymer content in the API Group I and / or Group II base oil as diluent.Base Oil:

[0030] The lubricating oil compositions herein include one or more base oils having a lubricating viscosity. Base oils suitable for use in formulating the lubricating oil compositions suitable for use in lubricating an internal combustion engine fueled with the alternative fuels as described herein may be selected from any suitable synthetic or natural oils or mixtures thereof having a suitable lubricating viscosity. Natural oils may include animal oils and vegetable oils (e.g., castor oil, lard oil) as well as mineral oils such as liquid petroleum oils and solvent treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic types. Oils derived from coal or shale may also be suitable. Further, oil derived from a gas-to-liquid process is also suitable. The base oil may have a kinematic viscosity at 100° C. (e.g. KV100) of about 2 to about 15 cSt, as measured by ASTM D2270-10.

[0031] The base oil as used in lubricants described herein may be a single base oil or may be a mixture of two or more base oils. In one embodiment, the one or more base oil(s) may be selected from any of the base oils in Groups I to IV as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. In other embodiments, the one or more base oils of lubricating viscosity preferably include only API Group I base oils, API Group II base oils, or combinations thereof. Preferably, the one or more base oils of lubricating viscosity includes one or more API Group I base oils, one or more API Group II base oils, and one or more API Group III base oils. In some embodiments, the one or more base oils of lubricating viscosity includes one or more API Group III base oils. In alternative embodiments, the one or more base oils include one or more API Group I base oils, one or more API Group II base oils, or combinations thereof. In alternative embodiments, the one or more base oils include one or more API Group II base oil. As discussed more below, if API Group I and / or API Group II base oils are used (which are widely accepted as lower quality base oils), the lubricating oil compositions herein also include select amounts of magnesium metal, which unexpectedly overcomes any negative performance debits of the lower quality base oils. Such base oil groups are shown in Table 1 as follows:TABLE 1Base oil CategorySulfur (%)Saturates (%)Viscosity IndexAPI Group I>0.03and / or<9080 to 120API Group II≤0.03and≥9080 to 120API Group III≤0.03and≥90≥120API Group IVAll polyalphaolefins (PAOs)API Group VAll others not included inGroups I, II, III, or IV

[0032] API Group III base oils may include oil derived from Fischer-Tropsch synthesized hydrocarbons. Fischer-Tropsch synthesized hydrocarbons are made from synthesis gas containing H2 and CO using a Fischer-Tropsch catalyst. Such hydrocarbons typically require further processing in order to be useful as the base oil. These types of oils are commonly referred to as gas-to-liquids (GTLs). For example, the hydrocarbons may be hydroisomerized using processes disclosed in U.S. Pat. No. 6,103,099 or 6,180,575; hydrocracked and hydroisomerized using processes disclosed in U.S. Pat. No. 4,943,672 or 6,096,940; dewaxed using processes disclosed in U.S. Pat. No. 5,882,505; or hydroisomerized and dewaxed using processes disclosed in U.S. Pat. Nos. 6,013,171; 6,080,301; or 6,165,949.

[0033] API Group IV base oils, PAOs, are typically derived from monomers having from 4 to 30, or from 4 to 20, or from 6 to 16 carbon atoms. Examples of PAOs that may be used in the present invention include those derived from octene, decene, mixtures thereof, and the like. PAOs may have a kinematic viscosity of from 2 to 15, or from 3 to 12, or from 4 to 8 cSt at 100° C., as measured by ASTM D2270-10. Examples of PAOs include 4 cSt at 100° C. PAOs, 6 cSt at 100° C. PAOs, and mixtures thereof.

[0034] The base oil(s) are combined with an additive composition as disclosed in embodiments herein to provide a lubricating oil composition for lubricating the crankcase of an internal combustion engine fueled with a gaseous fuel having an auto-ignition temperature greater than about 700K. Accordingly, the base oil may be present in the lubricating oil composition in an amount greater than about 75 wt % based on the total weight of the lubricating oil composition. In some embodiments, the base oil may be present in the lubricating oil composition in an amount greater than about 80 wt % based on the total weight of the lubricating oil composition. In some embodiments, the base oil may be present in the lubricating oil composition in an amount greater than about 85 wt % based on the total weight of the lubricating oil composition.Detergent System

[0035] The detergent systems of the lubricating oil compositions herein include one or more metal-containing detergents, preferably one or more overbased based metal-containing detergents, and more preferably one or more overbased magnesium-containing detergent providing a certain content of magnesium to the compositions. In one embodiment, the overbased magnesium-containing detergent(s) provide at least about 2 mmol of magnesium per 100 grams of lubricant, and more preferably about 4 to about 12 mmol of magnesium per 100 grams of the lubricating compositions herein as discussed more below (and, in some embodiments, at least about 1000 ppm of magnesium, or about 1000 ppm to about 3000 ppm of magnesium, or about 2000 ppm to about 3000 ppm, or about 2500 ppm to about 3000 ppm of magnesium). In some embodiments, the overbased detergents herein have a total base number (TBN) of at least about 200 mg KOH / g (preferably about 240 to about 450 mg KOH / g or about 250 to about 420 mg KOH / g) measured by ASTM D2896, and if used, neutral to low-based or neutral detergents have a total base number (TBN) of 50 mg KOH / g or below as measured by ASTM D2896. Suitable detergents and their methods of preparation are described, for instance, in greater detail in numerous patent publications, including U.S. Pat. Nos. 7,732,390; 4,165,291, and / or 4,206,062 (and references cited therein), which are incorporated herein by reference.

[0036] In embodiments, suitable detergent substrates (e.g., sulfonates or phenates) may be salted with an alkali or alkaline earth metal, which is preferably magnesium. In approaches or embodiments, the detergent systems herein preferably include an overbased magnesium-containing metal detergent having a TBN of at least about 200 (ASTM D2896) (preferably providing at least about 2 mmol or about 4 to about 12 mmol of magnesium per 100 grams of lubricant) to the lubricating oil composition. In other approaches or embodiments, the detergent systems provide at least about 1000 ppm of magnesium (or, as discussed above, about 1000 ppm to about 3000 ppm of magnesium, or about 2000 ppm to about 3000 ppm, or about 2500 ppm to about 3000 ppm of magnesium). In a further embodiment, the overbased magnesium-based detergent is an overbased magnesium sulfonate detergent.

[0037] In embodiments and subject to the discussions on the detergent systems herein, suitable detergents may include linear or branched alkali or alkaline earth metal salts, such as calcium, sodium, or magnesium salts, of petroleum sulfonic acids and long chain mono- or di-alkylaryl sulfonic acids with the aryl group being benzyl, tolyl, and xylyl and / or various phenates or derivatives of phenates. Examples of suitable detergents include (subject to the noted TBN and metal limitations discussed herein), but are not limited to, low-based, neutral, and / or overbased variations of the following detergents: magnesium phenates, magnesium sulfur containing phenates, magnesium sulfonates, magnesium calixarates, magnesium salixarates, magnesium salicylates, magnesium carboxylic acids, magnesium phosphorus acids, magnesium mono- and / or di-thiophosphoric acids, magnesium alkyl phenols, magnesium sulfur coupled alkyl phenol compounds, magnesium methylene bridged phenols, calcium phenates, calcium sulfur containing phenates, calcium sulfonates, calcium calixarates, calcium salixarates, calcium salicylates, calcium carboxylic acids, calcium phosphorus acids, calcium mono- and / or di-thiophosphoric acids, calcium alkyl phenols, calcium sulfur coupled alkyl phenol compounds, calcium methylene bridged phenols, sodium phenates, sodium sulfur containing phenates, sodium sulfonates, sodium calixarates, sodium salixarates, sodium salicylates, sodium carboxylic acids, sodium phosphorus acids, sodium mono- and / or di-thiophosphoric acids, sodium alkyl phenols, sodium sulfur coupled alkyl phenol compounds, or sodium methylene bridged phenols. Preferably, the detergent systems herein include at least overbased magnesium detergents providing the metal amounts noted above.

[0038] The terminology “overbased” relates to metal salts, wherein the amount of metal present exceeds the stoichiometric amount. Such salts may have a conversion level in excess of 100% (i.e., they may comprise more than 100% of the theoretical amount of metal needed to convert the acid to its “normal,”“neutral” salt). The expression “metal ratio,” often abbreviated as MR, is used to designate the ratio of total chemical equivalents of metal in the overbased salt to chemical equivalents of the metal in a neutral salt according to known chemical reactivity and stoichiometry. In a normal or neutral salt, the metal ratio is one and in an overbased salt, MR, is greater than one. They are commonly referred to as overbased, hyperbased, or superbased salts and may be salts of organic sulfur acids. As used herein, an overbased detergent herein may have, in one embodiment, a total base number (TBN) of about 200 mg KOH / gram or higher, about 240 mg KOH / gram or greater, about 250 mg KOH / gram or greater, about 280 mg KOH / gram or greater, or about 300 mg KOH / gram or greater (in other approaches, about 240 to about 450 mg KOH / g or about 250 to about 420 mg KOH / g). As used herein, total base number or TBN of a detergent additive is determined using ASTM D2896. When such detergent compositions are formed in an inert diluent, e.g. a process oil, usually a mineral oil, the total base number reflects the basicity of the overall composition including diluent, and any other materials (e.g., promoter, etc.) that may be contained in the detergent composition.

[0039] Examples of suitable overbased detergents include (subject to the TBN and metal limitations noted herein), but are not limited to, overbased magnesium phenates, overbased magnesium sulfur containing phenates, overbased magnesium sulfonates, overbased magnesium calixarates, overbased magnesium salixarates, overbased magnesium salicylates, overbased magnesium carboxylic acids, overbased magnesium phosphorus acids, overbased magnesium mono- and / or di-thiophosphoric acids, overbased magnesium alkyl phenols, overbased magnesium sulfur coupled alkyl phenol compounds, or overbased magnesium methylene bridged phenols.

[0040] In some embodiments, the detergent systems used in the lubricants herein includes an overbased magnesium detergent (preferably an overbased magnesium sulfonate detergent) having a total base number (TBN) of at least about 200 mg KOH / g and, in other approaches, a TBN of about 200 to about 450 and, in other approaches, about 200 to about 425 or about 250 to about 425, or about 280 to about 425 (ASTM D2896). The above described TBN values reflect those of finished detergent components that have been diluted in a base oil.

[0041] In other embodiments, the detergent systems include select amounts of such overbased magnesium-containing metal detergents (e.g., overbased magnesium sulfonate detergents) to provide at least about 2 mmol or about 2 to about 12 mmol of magnesium, in other approaches, about 4 to about 12 mmol of magnesium, or about 6 to about 12 mmol of magnesium to the lubricating oil compositions herein, or about 8 to about 12 mmol of magnesium per 100 grams of lubricant. As shown in the Examples below, having such minimum amounts of magnesium is advantageous to counteract any negative performance benefits of the lower quality API Group I and / or Group II base oils. In yet other approaches, the lubricants herein include at least about 1000 ppm of magnesium, at least about 1500 ppm of magnesium, or at least about 2000 ppm of magnesium (and preferably about 5000 ppm or less, about 4500 ppm or less, about 4000 ppm or less, about 3500 ppm or less of magnesium, or about 3000 ppm or less). In other approaches or embodiments, the lubricants include about 1000 ppm of magnesium to about 3000 ppm of magnesium, or about 2000 ppm to about 3000 ppm of magnesium, or about 2500 ppm to about 3000 ppm of magnesium. As shown in the Examples, it was surprising that magnesium contributions could overcome performance deficiencies of the lower quality base oils in the context of SPI in hydrogen-fueled engines.Lubricating Oil Compositions:

[0042] The lubricating oil composition herein include one or more of a select base oil blend, a specific viscosity modifier olefin copolymer and / or select detergent system. The inclusion of either the lower molecular weight and / or or higher molecular weight viscosity modifier olefin copolymer aids, in some approaches, in achieving one or more of the desired viscosity (KV100 and / or HTHS), NOACK, and / or low SPI of the resulting lubricating oil compositions when used to lubricate the alternative fueled engines as shown in the Example below. Other approaches combine the base oil(s) and the viscosity modifier olefin copolymer with a select detergent system to minimize SPI in such alternative fueled engines.

[0043] The resulting viscosity can be measured, for example, by measuring its KV100 and / or high temperature high shear viscosity (HTHS). KV100 refers to the kinematic viscosity of a lubricating composition measured at 100° C., typically expressed in mm2 / s or centistokes (cSt), as determined in accordance with ASTM D445 or an equivalent standard method. In one embodiment, the lubricating oil compositions herein has a kinematic viscosity at 100° C. (KV100) of about 14 cSt or less, or about 13.5 cSt or less, or in another embodiments, about 11 cSt or less (preferably, about 6 to about 14 cSt or about 6 to about 11 cSt). High Temperature High Shear (HTHS) viscosity refers to a dynamic viscosity under high shear conditions and is also typically reported in cSt, as determined in accordance with one or more of ASTM D4683, D4741, and / or D5471. In one embodiment, the lubricating oil compositions herein has a HTHS viscosity at 150° C. of about 4.0 cSt or less, or in another embodiments, about 3.7 cSt or less (preferably, about 2.3 to about 3.7 cSt or about 2.6 to about 3.5 cSt).

[0044] NOACK volatility measures engine oil evaporation loss at higher temperatures (200° C. for 1 hour) and is reported as percent or weight fraction lost as determined in accordance with ASTM D5800. In one embodiment, the lubricating oil compositions herein have a NOACK volatility (200° C. for 1 hour) about 20% or less, or in another embodiments, about 18% or less, or about 15% or less, or about 13.5% or less (preferably, about 12 to about 18% or about 12 to about 16%).

[0045] Stochastic pre-ignition (SPI) refers to an unintended premature combustion event of the primary fuel charge, which results in early detonation, misfiring, and engine knock. SPI for a hydrogen-fueled internal combustion engine may be evaluated at the Graz University of Technology (Austria) and is reported as events per 1000 cycles at 1350 rpm and 17 bar brake mean effective pressure (BMEP). In one embodiment, the lubricating oil compositions herein achieve about 65 SPI counts or less per 1000 cycles, or about 50 SPI counts or less per 1000 cycles, or about 40 SPI counts or less per 1000 cycles, or about 20 SPI counts or less per 1000 cycles. When the base oil, detergent, and / or viscosity modifier is not correctly selected, the SPI events increase to undesirable levels (which is generally greater than 100 SPI events per 1000 cycles).Alternative Combustion Fuels

[0046] The lubricating oil compositions herein are configured for lubricating the crankcase of an internal combustion engine being fueled with an alternative combustion fuel, which for purposes of this disclosure, is a fuel having an auto-ignition temperature of at least about 700K, at least about 800K, or at least about 850K. In other approaches, the alternative combustion fuels have auto-ignition temperatures of up to about 900K, up to about 880K, or up to about 860K. Such alternative combustion fuels include, but are not limited to, hydrogen fuel (auto-ignition temperature of about 858K) that can be gaseous hydrogen fuel, natural gas fuel (auto-ignition temperature of about 813K) that can be compressed natural gas and / or liquid natural gas, and the like. In some embodiments, the fuel having an auto-ignition temperature greater than about 700K is hydrogen fuel. Preferably, the alternative combustion fuels herein that are suited for use with the lubricating compositions herein include gaseous hydrogen fuel that is combusted in the engine in a gaseous state.

[0047] In some aspects, this disclosure provides a method for the lubrication of a crankcase of an internal combustion engine with a lubricating oil composition and combusting a fuel having an auto-ignition temperature greater than about 700K in the internal combustion engine.Other Additives

[0048] The lubricating oil compositions described herein may also include other additives of the type used in crankcase lubricating compositions in addition to the viscosity modifier(s), detergent(s), and other components described above. Such additives include, but are not limited to, antioxidant(s), phosphorus-containing components, corrosion inhibitor(s), antirust additives, antifoam agent(s), demulsifier(s), pour point depressant(s), seal swell agent(s), and additional dispersant(s), additional friction modifier(s), and additional sulfur-containing component(s).

[0049] DISPERSANTS: The lubricating oil composition may optionally include one or more dispersants or mixtures thereof. Dispersants are often known as ashless-type dispersants because, prior to mixing in a lubricating oil composition, they do not contain ash-forming metals and they do not normally contribute any ash when added to a lubricant. Ashless type dispersants are characterized by a polar group attached to a relatively high molecular weight hydrocarbon chain. Typical ashless dispersants include N-substituted long chain alkenyl succinimides. Examples of N-substituted long chain alkenyl succinimides include polyisobutylene succinimide with the number average molecular weight of the polyisobutylene substituent being in the range about 350 to about 50,000, or to about 5,000, or to about 3,000, as measured by GPC. Succinimide dispersants and their preparation are disclosed, for instance in U.S. Pat. No. 7,897,696 or U.S. Pat. No. 4,234,435. The alkenyl substituent may be prepared from polymerizable monomers containing about 2 to about 16, or about 2 to about 8, or about 2 to about 6 carbon atoms. Succinimide dispersants are typically the imide formed from a polyamine, typically a poly(ethyleneamine).

[0050] Preferred amines are selected from polyamines and hydroxyamines. Examples of polyamines that may be used include, but are not limited to, diethylene triamine (DETA), triethylene tetramine (TETA), tetraethylene pentamine (TEPA), and higher homologues such as pentaethylamine hexamine (PEHA), and the like.

[0051] A suitable heavy polyamine is a mixture of polyalkylene-polyamines comprising small amounts of lower polyamine oligomers such as TEPA and PEHA (pentaethylene hexamine) but primarily oligomers with 6 or more nitrogen atoms, 2 or more primary amines per molecule, and more extensive branching than conventional polyamine mixtures. A heavy polyamine preferably includes polyamine oligomers containing 7 or more nitrogens per molecule and with 2 or more primary amines per molecule. The heavy polyamine comprises more than 28 wt. % (e.g. >32 wt. %) total nitrogen and an equivalent weight of primary amine groups of 120-160 grams per equivalent.

[0052] In some approaches, suitable polyamines are commonly known as PAM and contain a mixture of ethylene amines where TEPA and pentaethylene hexamine (PEHA) are the major part of the polyamine, usually less than about 80%.

[0053] Typically, PAM has 8.7 to 8.9 milliequivalents of primary amine per gram (an equivalent weight of 115 to 112 grams per equivalent of primary amine) and a total nitrogen content of about 33-34 wt. %. Heavier cuts of PAM oligomers with practically no TEPA and only very small amounts of PEHA but containing primarily oligomers with more than 6 nitrogens and more extensive branching, may produce dispersants with improved dispersancy.

[0054] In an embodiment the present disclosure further comprises at least one polyisobutylene succinimide dispersant derived from polyisobutylene with a number average molecular weight in the range about 350 to about 50,000, or to about 5000, or to about 3000, as determined by GPC. The polyisobutylene succinimide may be used alone or in combination with other dispersants.

[0055] In some embodiments, polyisobutylene, when included, may have greater than 50 mol %, greater than 60 mol %, greater than 70 mol %, greater than 80 mol %, or greater than 90 mol % content of terminal double bonds. Such PIB is also referred to as highly reactive PIB (“HR-PIB”). HR-PIB having a number average molecular weight ranging from about 800 to about 5000, as determined by GPC, is suitable for use in embodiments of the present disclosure. Conventional PIB typically has less than 50 mol %, less than 40 mol %, less than 30 mol %, less than 20 mol %, or less than 10 mol % content of terminal double bonds.

[0056] An HR-PIB having a number average molecular weight ranging from about 900 to about 3000 may be suitable, as determined by GPC. Such HR-PIB is commercially available, or can be synthesized by the polymerization of isobutene in the presence of a non-chlorinated catalyst such as boron trifluoride, as described in U.S. Pat. No. 4,152,499 to Boerzel, et al. and U.S. Pat. No. 5,739,355 to Gateau, et al. When used in the aforementioned thermal ene reaction, HR-PIB may lead to higher conversion rates in the reaction, as well as lower amounts of sediment formation, due to increased reactivity. A suitable method is described in U.S. Pat. No. 7,897,696.

[0057] In one embodiment, the present disclosure further comprises at least one dispersant derived from polyisobutylene succinic anhydride (“PIBSA”). The PIBSA may have an average of between about 1.0 and about 2.0 succinic acid moieties per polymer. The % actives of the alkenyl or alkyl succinic anhydride can be determined using a chromatographic technique. This method is described in column 5 and 6 in U.S. Pat. No. 5,334,321. The percent conversion of the polyolefin is calculated from the % actives using the equation in column 5 and 6 in U.S. Pat. No. 5,334,321. Unless stated otherwise, all percentages are in weight percent and all molecular weights are number average molecular weights determined by gel permeation chromatography (GPC) using commercially available polystyrene standards (with a number average molecular weight of 180 to about 18,000 as the calibration reference).

[0058] In one embodiment, the dispersant may be derived from a polyalphaolefin (PAO) succinic anhydride. In one embodiment, the dispersant may be derived from olefin maleic anhydride copolymer. As an example, the dispersant may be described as a poly-PIBSA. In an embodiment, the dispersant may be derived from an anhydride which is grafted to an ethylene-propylene copolymer.

[0059] A suitable class of nitrogen-containing dispersants may be derived from olefin copolymers (OCP), more specifically, ethylene-propylene dispersants which may be grafted with maleic anhydride. A more complete list of nitrogen-containing compounds that can be reacted with the functionalized OCP are described in U.S. Pat. Nos. 7,485,603; 7,786,057; 7,253,231; 6,107,257; and 5,075,383; and / or are commercially available.

[0060] One class of suitable dispersants may also be Mannich bases. Mannich bases are materials that are formed by the condensation of a higher molecular weight, alkyl-substituted phenol, a polyalkylene polyamine, and an aldehyde such as formaldehyde. Mannich bases are described in more detail in U.S. Pat. No. 3,634,515.

[0061] A suitable class of dispersants may also be high molecular weight esters or half ester amides. A suitable dispersant may also be post-treated by conventional methods by a reaction with any of a variety of agents. Among these are boron, urea, thiourea, dimercaptothiadiazoles, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, maleic anhydride, nitriles, epoxides, carbonates, cyclic carbonates, hindered phenolic esters, and phosphorus compounds. U.S. Pat. Nos. 7,645,726; 7,214,649; and 8,048,831 are incorporated herein by reference in their entireties.

[0062] In addition to the carbonate and boric acids post-treatments both the compounds may be post-treated, or further post-treatment, with a variety of post-treatments designed to improve or impart different properties. Such post-treatments include those summarized in columns 27-29 of U.S. Pat. No. 5,241,003, hereby incorporated by reference. Such treatments include, treatment with: Inorganic phosphorous acids or anhydrates (e.g., U.S. Pat. Nos. 3,403,102 and 4,648,980); Organic phosphorous compounds (e.g., U.S. Pat. No. 3,502,677); Phosphorous pentasulfides; Boron compounds as already noted above (e.g., U.S. Pat. Nos. 3,178,663 and 4,652,387); Carboxylic acid, polycarboxylic acids, anhydrides and / or acid halides (e.g., U.S. Pat. Nos. 3,708,522 and 4,948,386); Epoxides polyepoxiates or thioexpoxides (e.g., U.S. Pat. Nos. 3,859,318 and 5,026,495); Aldehyde or ketone (e.g., U.S. Pat. No. 3,458,530); Carbon disulfide (e.g., U.S. Pat. No. 3,256,185); Glycidol (e.g., U.S. Pat. No. 4,617,137); Urea, thiourea or guanidine (e.g., U.S. Pat. Nos. 3,312,619; 3,865,813; and British Patent GB 1,065,595); Organic sulfonic acid (e.g., U.S. Pat. No. 3,189,544 and British Patent GB 2,140,811); Alkenyl cyanide (e.g., U.S. Pat. Nos. 3,278,550 and 3,366,569); Diketene (e.g., U.S. Pat. No. 3,546,243); A diisocyanate (e.g., U.S. Pat. No. 3,573,205); Alkane sultone (e.g., U.S. Pat. No. 3,749,695); 1,3-Dicarbonyl Compound (e.g., U.S. Pat. No. 4,579,675); Sulfate of alkoxylated alcohol or phenol (e.g., U.S. Pat. No. 3,954,639); Cyclic lactone (e.g., U.S. Pat. Nos. 4,617,138; 4,645,515; 4,668,246; 4,963,275; and 4,971,711); Cyclic carbonate or thiocarbonate linear monocarbonate or polycarbonate, or chloroformate (e.g., U.S. Pat. Nos. 4,612,132; 4,647,390; 4,648,886; 4,670,170); Nitrogen-containing carboxylic acid (e.g., U.S. Pat. No. 4,971,598 and British Patent GB 2,140,811); Hydroxy-protected chlorodicarbonyloxy compound (e.g., U.S. Pat. No. 4,614,522); Lactam, thiolactam, thiolactone or dithiolactone (e.g., U.S. Pat. Nos. 4,614,603 and 4,666,460); Cyclic carbonate or thiocarbonate, linear monocarbonate or polycarbonate, or chloroformate (e.g., U.S. Pat. Nos. 4,612,132; 4,647,390; 4,646,860; and 4,670,170); Nitrogen-containing carboxylic acid (e.g., U.S. Pat. No. 4,971,598 and British Patent GB 2,440,811); Hydroxy-protected chlorodicarbonyloxy compound (e.g., U.S. Pat. No. 4,614,522); Lactam, thiolactam, thiolactone or dithiolactone (e.g., U.S. Pat. Nos. 4,614,603, and 4,666,460); Cyclic carbamate, cyclic thiocarbamate or cyclic dithiocarbamate (e.g., U.S. Pat. Nos. 4,663,062 and 4,666,459); Hydroxyaliphatic carboxylic acid (e.g., U.S. Pat. Nos. 4,482,464; 4,521,318; 4,713,189); Oxidizing agent (e.g., U.S. Pat. No. 4,379,064); Combination of phosphorus pentasulfide and a polyalkylene polyamine (e.g., U.S. Pat. No. 3,185,647); Combination of carboxylic acid or an aldehyde or ketone and sulfur or sulfur chloride (e.g., U.S. Pat. Nos. 3,390,086; 3,470,098); Combination of a hydrazine and carbon disulfide (e.g. U.S. Pat. No. 3,519,564); Combination of an aldehyde and a phenol (e.g., U.S. Pat. Nos. 3,649,229; 5,030,249; 5,039,307); Combination of an aldehyde and an O-diester of dithiophosphoric acid (e.g., U.S. Pat. No. 3,865,740); Combination of a hydroxyaliphatic carboxylic acid and a boric acid (e.g., U.S. Pat. No. 4,554,086); Combination of a hydroxyaliphatic carboxylic acid, then formaldehyde and a phenol (e.g., U.S. Pat. No. 4,636,322); Combination of a hydroxyaliphatic carboxylic acid and then an aliphatic dicarboxylic acid (e.g., U.S. Pat. No. 4,663,064); Combination of formaldehyde and a phenol and then glycolic acid (e.g., U.S. Pat. No. 4,699,724); Combination of a hydroxyaliphatic carboxylic acid or oxalic acid and then a diisocyanate (e.g. U.S. Pat. No. 4,713,191); Combination of inorganic acid or anhydride of phosphorus or a partial or total sulfur analog thereof and a boron compound (e.g., U.S. Pat. No. 4,857,214); Combination of an organic diacid then an unsaturated fatty acid and then a nitrosoaromatic amine optionally followed by a boron compound and then a glycolating agent (e.g., U.S. Pat. No. 4,973,412); Combination of an aldehyde and a triazole (e.g., U.S. Pat. No. 4,963,278); Combination of an aldehyde and a triazole then a boron compound (e.g., U.S. Pat. No. 4,981,492); Combination of cyclic lactone and a boron compound (e.g., U.S. Pat. Nos. 4,963,275 and 4,971,711). The above-mentioned patents are herein incorporated in their entireties.

[0063] The TBN of a suitable dispersant may be from about 10 to about 65 mg KOH / g dispersant, on an oil-free basis, which is comparable to about 5 to about 30 TBN if measured on a dispersant sample containing about 50% diluent oil. TBN is measured by the method of ASTM D2896.

[0064] In yet other embodiments, the optional dispersant additive may be a hydrocarbyl substituted succinamide or succinimide dispersant. In approaches, the hydrocarbyl substituted succinamide or succinimide dispersant may be derived from a hydrocarbyl substituted acylating agent reacted with a polyalkylene polyamine and wherein the hydrocarbyl substituent of the succinamide or the succinimide dispersant is a linear or branched hydrocarbyl group having a number average molecular weight of about 250 to about 5,000 as measured by GPC using polystyrene as a calibration reference.

[0065] In some approaches, the polyalkylene polyamine used to form the dispersant has the Formulawherein each R and R′, independently, is a divalent C1 to C6 alkylene linker, each R1 and R2, independently, is hydrogen, a C1 to C6 alkyl group, or together with the nitrogen atom to which they are attached form a 5- or 6-membered ring optionally fused with one or more aromatic or non-aromatic rings, and n is an integer from 0 to 8. In other approaches, the polyalkylene polyamine is selected from the group consisting of a mixture of polyethylene polyamines having an average of 5 to 7 nitrogen atoms, triethylenetetramine, tetraethylenepentamine, and combinations thereof.The dispersant, if present, can be used in an amount sufficient to provide up to about 20 wt %, based upon the final weight of the lubricating oil composition. Another amount of the dispersant that can be used may be about 0.1 wt % to about 15 wt %, or about 0.1 wt % to about 10 wt %, about 0.1 to 8 wt %, or about 1 wt % to about 10 wt %, or about 1 wt % to about 8 wt %, or about 1 wt % to about 6 wt %, based upon the final weight of the lubricating oil composition. In some embodiments, the lubricating oil composition utilizes a mixed dispersant system. A single type or a mixture of two or more types of dispersants in any desired ratio may be used.

[0067] ANTIWEAR AGENTS: The lubricating oil compositions herein also may optionally contain one or more antiwear agents. Examples of suitable antiwear agents include, but are not limited to, a metal thiophosphate; a metal dialkyldithiophosphate; a phosphoric acid ester or salt thereof, a phosphate ester(s); a phosphite; a phosphorus-containing carboxylic ester, ether, or amide; a sulfurized olefin; thiocarbamate-containing compounds including, thiocarbamate esters, alkylene-coupled thiocarbamates, dithiocarbamates, and / or bis(S-alkyldithiocarbamyl) disulfides; and mixtures thereof. A suitable antiwear agent may be a molybdenum dithiocarbamate, bis(dialkyl-dithiocarbamate), or alkylene bis(dialkyl-dithiocarbamate) and the like antiwear agents. The phosphorus containing antiwear agents are more fully described in European Patent 612 839. The metal in the dialkyl dithio phosphate salts may be an alkali metal, alkaline earth metal, aluminum, lead, tin, molybdenum, manganese, nickel, copper, titanium, or zinc. A useful antiwear agent may be zinc dialkyldithiophosphate.

[0068] Further examples of suitable antiwear agents include titanium compounds, tartrates, tartrimides, oil soluble amine salts of phosphorus compounds, sulfurized olefins, phosphites (such as dibutyl phosphite), phosphonates, thiocarbamate-containing compounds, such as thiocarbamate esters, thiocarbamate amides, thiocarbamic ethers, alkylene-coupled thiocarbamates, and bis(S-alkyldithiocarbamyl) disulfides. The tartrate or tartrimide may contain alkyl-ester groups, where the sum of carbon atoms on the alkyl groups may be at least 8. The antiwear agent may in one embodiment include a citrate.

[0069] The antiwear agent may be present in ranges including about 0 wt % to about 15 wt %, or about 0.01 wt % to about 10 wt %, or about 0.05 wt % to about 5 wt %, or about 0.1 wt % to about 3 wt % of the lubricating oil composition. In other embodiments, the compositions here may further include one or more oil-soluble molybdenum compounds, and if included, providing about 200 ppm or less of molybdenum, less than about 150 ppm, less than about 100 ppm, or less than about 50 ppm of molybdenum.

[0070] ANTIOXIDANTS: In some embodiments, the lubricating oil compositions herein may contain one or more antioxidants. Suitable antioxidants include phenolic antioxidants, aromatic amine antioxidants, sulfur containing antioxidants, and organic phosphites, among others.

[0071] Examples of phenolic antioxidants include 2,6-di-tert-butylphenol, liquid mixtures of tertiary butylated phenols, 2,6-di-tert-butyl-4-methylphenol, 4,4′-methylenebis(2,6-di-tert-butylphenol), 2,2′-methylenebis(4-methyl-6-ter-t-butylphenol), and mixed methylene-bridged polyalkyl phenols, and 4,4′-thiobis(2-methyl-6-tert-butylphenol), N,N′-di-sec-butyl-phenylenediamine, 4-iisopropylaminodiphenylamine, phenyl-alpha-naphthyl amine, phenyl-alpha-naphthyl amine, and ring-alkylated diphenylamines. Examples include the sterically hindered tertiary butylated phenols, bisphenols and cinnamic acid derivatives and combinations thereof.

[0072] Aromatic amine antioxidants include, but are not limited to diarylamines having the formula:wherein R′ and R″ each independently represents a substituted or unsubstituted aryl group having from 6 to 30 carbon atoms. Illustrative of substituents for the aryl group include aliphatic hydrocarbon groups such as alkyl having from 1 to 30 carbon atoms, hydroxy groups, halogen radicals, carboxylic acid or ester groups, or nitro groups.The aryl group is preferably substituted or unsubstituted phenyl or naphthyl, particularly wherein one or both of the aryl groups are substituted with at least one alkyl having from 4 to 30 carbon atoms, preferably from 4 to 18 carbon atoms, most preferably from 4 to 9 carbon atoms. It is preferred that one or both aryl groups be substituted, e.g. mono-alkylated diphenylamine, di-alkylated diphenylamine, or mixtures of mono- and di-alkylated diphenylamines.

[0074] Examples of diarylamines that may be used include, but are not limited to: diphenylamine; various alkylated diphenylamines, 3-hydroxydiphenylamine, N-phenyl-1,2-phenylenediamine, N-phenyl-1,4-phenylenediamine, monobutyldiphenyl-amine, dibutyl diphenylamine, monooctyldiphenylamine, dioctyldiphenylamine, monononyl diphenylamine, dinonyldiphenylamine, monotetradecyldiphenylamine, ditetradecyl diphenylamine, phenyl-alpha-naphthylamine, monooctyl phenyl-alpha-naphthylamine, phenyl-beta-naphthylamine, monoheptyldiphenylamine, diheptyl-diphenylamine, p-oriented styrenated diphenylamine, mixed butyloctyldi-phenylamine, and mixed octylstyryldiphenylamine.

[0075] The sulfur containing antioxidants include, but are not limited to, sulfurized olefins that are characterized by the type of olefin used in their production and the final sulfur content of the antioxidant. High molecular weight olefins, i.e., those olefins having an average molecular weight of 168 to 351 g / mole, are preferred. Examples of olefins that may be used include alpha-olefins, isomerized alpha-olefins, branched olefins, cyclic olefins, and combinations of these.

[0076] Alpha-olefins include, but are not limited to, any C4 to C25 alpha-olefins. Alpha-olefins may be isomerized before the sulfurization reaction or during the sulfurization reaction. Structural and / or conformational isomers of the alpha olefin that contain internal double bonds and / or branching may also be used. For example, isobutylene is a branched olefin counterpart of the alpha-olefin 1-butene.

[0077] Sulfur sources that may be used in the sulfurization reaction of olefins include: elemental sulfur, sulfur monochloride, sulfur dichloride, sodium sulfide, sodium polysulfide, and mixtures of these added together or at different stages of the sulfurization process.

[0078] Unsaturated oils, because of their unsaturation, may also be sulfurized and used as an antioxidant. Examples of oils or fats that may be used include corn oil, canola oil, cottonseed oil, grapeseed oil, olive oil, palm oil, peanut oil, coconut oil, rapeseed oil, safflower seed oil, sesame seed oil, soybean oil, sunflower seed oil, tallow, and combinations of these.

[0079] The total amount of antioxidant in the lubricating oil composition described herein may be present in an amount to deliver up to about 200 ppm nitrogen, or up to about 150 ppm nitrogen, or about 100 to about 150 ppm nitrogen.

[0080] FRICTION MODIFIERS: In some embodiments, the lubricating oil compositions herein may also contain additional friction modifiers other than those contained in the friction modifier system described above. Suitable additional friction modifiers may comprise metal containing and metal-free friction modifiers and may include, but are not limited to, imidazolines, amides, amines, succinimides, alkoxylated amines, alkoxylated ether amines, amine oxides, amidoamines, nitriles, betaines, quaternary amines, imines, amine salts, amino guanidine, alkanolamides, phosphonates, metal-containing compounds, glycerol esters, sulfurized fatty compounds and olefins, sunflower oil other naturally occurring plant or animal oils, dicarboxylic acid esters, esters or partial esters of a polyol and one or more aliphatic or aromatic carboxylic acids, and the like.

[0081] Suitable friction modifiers may contain hydrocarbyl groups that are selected from straight chain, branched chain, or aromatic hydrocarbyl groups or mixtures thereof, and such hydrocarbyl groups may be saturated or unsaturated. The hydrocarbyl groups may be composed of carbon and hydrogen or hetero atoms such as sulfur or oxygen. The hydrocarbyl groups may range from 12 to 25 carbon atoms. In some embodiments the friction modifier may be a long chain fatty acid ester. In another embodiment the long chain fatty acid ester may be a mono-ester, or a di-ester, or a (tri)glyceride. The friction modifier may be a long chain fatty amide, a long chain fatty ester, a long chain fatty epoxide derivative, or a long chain imidazoline.

[0082] Other suitable friction modifiers may include organic, ashless (metal-free), nitrogen-free organic friction modifiers. Such friction modifiers may include esters formed by reacting carboxylic acids and anhydrides with alkanols and generally include a polar terminal group (e.g. carboxyl or hydroxyl) covalently bonded to an oleophilic hydrocarbon chain. An example of an organic ashless nitrogen-free friction modifier is known generally as glycerol monooleate (GMO) which may contain mono-, di-, and tri-esters of oleic acid. Other suitable friction modifiers are described in U.S. Pat. No. 6,723,685.

[0083] Aminic friction modifiers may include amines or polyamines. Such compounds can have hydrocarbyl groups that are linear, either saturated or unsaturated, or a mixture thereof and may contain from 12 to 25 carbon atoms. Further examples of suitable friction modifiers include alkoxylated amines and alkoxylated ether amines. Such compounds may have hydrocarbyl groups that are linear, either saturated, unsaturated, or a mixture thereof. They may contain from about 12 to about 25 carbon atoms. Examples include ethoxylated amines and ethoxylated ether amines.

[0084] The amines and amides may be used as such or in the form of an adduct or reaction product with a boron compound such as a boric oxide, boron halide, metaborate, boric acid or a mono-, di- or tri-alkyl borate. Other suitable friction modifiers are described in U.S. Pat. No. 6,300,291.

[0085] If the additional friction modifiers contain nitrogen, such additional friction modifiers may be present in the lubricating oil composition in any amount as long as the performance requirements are not compromised.

[0086] CORROSION INHIBITORS: Other rust or corrosion inhibitors may also be included in the lubricating oil compositions described herein. Such materials include monocarboxylic acids and polycarboxylic acids. Examples of suitable monocarboxylic acids are octanoic acid, decanoic acid and dodecanoic acid. Suitable polycarboxylic acids include dimer and trimer acids such as are produced from such acids as tall oil fatty acids, oleic acid, linoleic acid, or the like.

[0087] Another useful type of rust inhibitor may be alkenyl succinic acid and alkenyl succinic anhydride corrosion inhibitors such as, for example, tetrapropenylsuccinic acid, tetrapropenylsuccinic anhydride, tetradecenylsuccinic acid, tetradecenylsuccinic anhydride, hexadecenylsuccinic acid, hexadecenylsuccinic anhydride, and the like. Also useful are the half esters of alkenyl succinic acids having 8 to 24 carbon atoms in the alkenyl group with alcohols such as the polyglycols. Other suitable rust or corrosion inhibitors include ether amines, acid phosphates, amines, polyethoxylated compounds such as ethoxylated amines, ethoxylated phenols, and ethoxylated alcohols, imidazolines, aminosuccinic acids or derivatives thereof, and the like. Mixtures of such rust or corrosion inhibitors may be used. The total amount of corrosion inhibitor, when present in the lubricating composition described herein may range up to 2.0 wt % or from 0.01 to 1.0 wt % based on the total weight of the lubricating composition.

[0088] DEMULSIFIERS: Demulsifiers may also be included in the compositions herein and may include trialkyl phosphates, and various polymers and copolymers of ethylene glycol, ethylene oxide, propylene oxide, or mixtures thereof, including polyethylene oxides, polypropylene oxides and (ethylene oxide-propylene oxide) polymers. When present, the amount of demulsifier in the lubricating oil composition may be up about 0.05 wt, or up to about 0.02 wt %, or below about 0.015 wt % based on the total weight of the lubricating oil composition.

[0089] ANTIFOAM AGENTS: Antifoam agents used to reduce or prevent the formation of stable foam include silicones, polyacrylates, or organic polymers. Foam inhibitors that may be useful in the compositions of the disclosed invention include polysiloxanes, copolymers of ethyl acrylate and 2-ethylhexylacrylate and optionally vinyl acetate. When present, the amount of antifoam in the lubricating oil composition may be up about 0.1 wt, or up to about 0.05 wt %, or below about 0.04 wt % based on the total weight of the lubricating oil composition.

[0090] POUR POINT DEPRESSANTS: The lubricating oil compositions herein may optionally contain one or more pour point depressants. Suitable pour point depressants may include esters of maleic anhydride-styrene, polymethacrylates, polymethylmethacrylates, polyacrylates or polyacrylamides or mixtures thereof. Pour point depressants, when present, may be present in amount from about 0.001 wt % to about 0.04 wt %, based upon the total weight of the lubricant.

[0091] In general terms, a lubricating oil composition described herein may include additive components in the ranges listed in Table 2.TABLE 2Wt. %Wt. %(Suitable(PreferredComponentEmbodiments)Embodiments)Detergent Systems1.0-5.01.0-3.0Viscosity Modifier OCP 0.5-2.00.7-1.8(active Polymer)Dispersant Systems 2.0-15.0 4.0-10.0Antioxidant(s)1.0-5.01.0-3.0Ashless TBN booster(s)0.0-1.00.01-0.5 Corrosion inhibitor(s)0.0-5.00.0 -2.0 Metal dihydrocarbyldi-0.0-6.00.5-2.0thiophosphate(s)Ash-free phosphorus0.0-6.00.0-4.0compound(s)Antifoaming agent(s)0.0-1.00.001-0.15 Other Antiwear agent(s)0.0-1.00.0-0.8Pour point0.0-1.00.00-0.5 depressant(s)Viscosity index 0.0-15.0 1.0-10.0improver(s)Friction modifier(s)0.00-1.0 0.01-0.8 Base oilBalanceBalanceTotal100100

[0092] The percentages of each component above represent the weight percent of each component, based upon the total weight of the lubricating oil composition containing the recited component. Additives used in formulating the compositions described herein may be blended into the base oil individually or in various sub-combinations. However, it may be suitable to blend all of the components concurrently using an additive concentrate (i.e., additives plus a diluent, such as a hydrocarbon solvent). The use of an additive concentrate takes advantage of the mutual compatibility afforded by the combination of ingredients when in the form of an additive concentrate. Also, the use of a concentrate reduces blending time and lessens the possibility of blending errors.

[0093] Unless the context of discussion herein suggests otherwise, the following definitions of terms are provided in order to clarify the meanings of certain terms as used herein.

[0094] The terms “lubricating oil,”“lubricant composition,”“lubricating composition,”“lubricant” and “lubricating oil composition” refer to a finished lubrication product comprising a major amount of a base oil plus a minor amount of an additive composition. As used herein, a major amount includes at least 50 weight percent or more and a minor amount includes less than 50 weight percent.

[0095] As used herein, the terms “additive package,”“additive concentrate,” and “additive composition,” refer the portion of the lubricating oil composition excluding the major amount of base oil.

[0096] As used herein, the term “hydrocarbyl substituent” or “hydrocarbyl group” is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having a predominantly hydrocarbon character. Each hydrocarbyl group is independently selected from hydrocarbon substituents, and substituted hydrocarbon substituents containing one or more of halo groups, hydroxyl groups, alkoxy groups, mercapto groups, nitro groups, nitroso groups, amino groups, pyridyl groups, furyl groups, imidazolyl groups, oxygen and nitrogen, and wherein no more than two non-hydrocarbon substituents are present for every ten carbon atoms in the hydrocarbyl group.

[0097] As used herein, the term “percent by weight” or “wt %”, unless expressly stated otherwise, means the percentage the recited component represents to the weight of the entire composition.

[0098] The terms “soluble,”“oil-soluble,” or “dispersible” used herein may, but does not necessarily, indicate that the compounds or additives are soluble, dissolvable, miscible, or capable of being suspended in the oil in all proportions. The foregoing terms do mean, however, that they are, for instance, soluble, suspendable, dissolvable, or stably dispersible in oil to an extent sufficient to exert their intended effect in the environment in which the oil is employed. Moreover, the additional incorporation of other additives may also permit incorporation of higher levels of a particular additive, if desired.

[0099] The term “alkyl” as employed herein refers to straight, branched, cyclic, and / or substituted saturated chain moieties from about 1 to about 200 carbon atoms.

[0100] The term “alkenyl” as employed herein refers to straight, branched, cyclic, and / or substituted unsaturated chain moieties from about 3 to about 30 carbon atoms.

[0101] The term “aryl” as employed herein refers to single and multi-ring aromatic compounds that may include alkyl, alkenyl, alkylaryl, amino, hydroxyl, alkoxy, halo substituents, and / or heteroatoms including, but not limited to, nitrogen, and oxygen.

[0102] As used herein, the “average number molecular weight” or “Mn” is determined by gel permeation chromatography (GPC) using commercially available polystyrene standards (with a Mn of about 180 to about 18,000 as the calibration reference).

[0103] It is to be understood that throughout the present disclosure, the terms “comprises,”“includes,”“contains,” etc. are considered open-ended and include any element, step, or ingredient not explicitly listed. The phrase “consists essentially of” is meant to include any expressly listed element, step, or ingredient and any additional elements, steps, or ingredients that do not materially affect the basic and novel aspects of the invention. The present disclosure also contemplates that any composition described using the terms, “comprises,”“includes,”“contains,” is also to be interpreted as including a disclosure of the same composition “consisting essentially of” or “consisting of” the specifically listed components thereof.Examples

[0104] A better understanding of the present disclosure and its many advantages may be clarified with the following examples. The following examples are illustrative and not limiting thereof in either scope or spirit. Those skilled in the art will readily understand that variations of the components, methods, steps, and devices described in these examples can be used. Unless noted otherwise or apparent from the context of discussion in the Example below and throughout this disclosure and claims, all percentages, ratios, and parts noted in this disclosure are by weight. Any standardized test method noted in the Examples, disclosure, or claims, unless apparent from the context of its use, refers to the version of the test method publicly available at the time of the filing of the present disclosure.Example 1

[0105] This Examples evaluated stochastic pre-ignition (SPI) per 1000 cycles using hydrogen-fueled internal combustion engines at the Graz University of Technology (Austria). SPI was evaluated using a test method developed at the Graz University of Technology using a 4 cylinder 2.0 liter turbocharged and direct-injection passenger car engine converted to run on hydrogen fuel. The engine had a compression ratio of 9.8 and the turbocharger utilized variable turbine geometry.

[0106] The evaluation of SPI involved dosing a small defined quantity of the lubricant (e.g., about 0.6 grams per kilowatt-hours) was introduced as aerosolized drops into the intake area of one individual cylinder using an external dosing system and a dosing lance. The result for each test lubricant was derived from the number of pre-ignition events at the relevant cylinder during the dosing phase, while the other cylinders act as statistical reference.

[0107] The oil dosing was carried out at a steady-state operating point over a one-hour test program based on the dosing release over time. The test program included a 45 minutes pre-heat-up phase and then an evaluation divided into five 12 minute phases: (1) a 12-minute pre-conditioning phase, (2) a 12-minute oil first dosing phase, (3) a 12-minute mid-conditioning phase, (4) a 12-minute second dosing phase, and (5) a final 12-minute post-conditioning phase. At the end of each test, the external oil dosing unit was cleaned and prepared for the next test. The tests were performed at an operating point of about 1350 rpm (rotations per minute) and a Brake mean effective pressure (BMEP) of about 17 bar. For purposes of this evaluation, an SPI event occurred if (i) the peak pressure in the dosing cylinder was 3 standard deviations or above the average peak pressure in the other cylinders and (ii) the crank angle degree of the dosing cylinder at 5 percent mass fraction of fuel burned (MFB05%) was also 3 standard deviations or below the other cylinders.

[0108] SPI in a hydrogen-fueled engine was evaluated using the lubricants of Table 3 below. All lubricants contained the same base additive package containing the same amount and type of dispersant, antioxidant, antifoam agent, pour point depressant, and friction modifier. All lubricants also included in the additive package an overbased magnesium sulfonate detergent having a TBN of about 400 (as measured by ASTM D2896) and providing about 2800 ppm magnesium to each lubricants (e.g., about 11.8 mmol of magnesium). Only the base oil type and the viscosity modifier copolymer were varied among the lubricants as shown in Tables 3 and 4 below. The viscosity modifier olefin copolymers used in this Example were as follows:

[0109] OCP 1: an ethylene propylene copolymer having approximately 49 weight percent ethylene monomer content, a weight average molecular weight of about 150,000 to about 160,000, a polydispersity index of about 1.5 to about 2.0, and had about 12.5 weight percent active copolymer in an API Group II diluent. OCP1 has a shear stability index (ASTM D6278) of 22.

[0110] OCP 2: an ethylene propylene copolymer having approximately 49 weight percent ethylene monomer content, a weight average molecular weight of about 270,000 to about 290,000, a polydispersity index of about 2.0 to about 2.5, and had about 7.5 weight percent active copolymer in an API Group II diluent. OCP2 has a shear stability index (ASTM D6278) of 50.TABLE 3LubricantsFluid 1Fluid 2Fluid 3Fluid 4Fluid 5Fluid 6Fluid 7Fluid 8OCP 1, active wt %—0.751.75——0.750.750.75OCP 2, active wt %———0.75————API GIII, wt %89.9583.9575.9579.95———42.0API GII, wt %—————83.95—42.0API GI, wt %————89.95—83.95—Mg Sulfonate, ppm Mg28002800280028002800280028002800Mmol Mg per 100 grams of lubricant11.811.811.811.811.811.811.811.8KV100, cSt11.477.8313.3710.086.829.4610.68.6HTHS150, cSt1.882.533.672.962.372.933.232.74NOACK, %12.412.517.21415.3—SPI / 1000 cycles208.9169.248.539.820.7463.5816.9144.44

[0111] As shown in Table 3 above, Fluid 1 includes an API group GIII base oil without an olefin copolymer and demonstrated high SPI in a hydrogen-fueled gas engine. Fluids 2 and 4 added 0.75 active weight percent of a low molecular weight olefin copolymer and a high molecular weight olefin copolymer (respectively), and both fluids demonstrated an improvement in SPI. As shown in Fluid 3, the addition of 1.75 active weight percent of the low molecular weight olefin copolymer provided even additional improvement in SPI as compared to Fluid 2. Fluids 5, 6, and 7 used lower quality base oils from API Group I or Group II. It was unexpected that the API Group I and II base oils, which are widely accepted as lower quality base oils, achieved improved SPI especially without an olefin copolymer (e.g., Fluid 5) and / or when combined with the selected olefin copolymer and / or at least about 1000 ppm of magnesium (e.g., Fluids 6 and 7). While Fluid 3 with API Group III base oils improved SPI, Fluid 8 that replaced some of the Group III base oil with a lower quality Group II base oil unexpectedly achieved an even lower SPI when combined with the lower molecular weight olefin copolymer.

[0112] It is to be understood that while the lubricating composition and compositions of this disclosure have been described in conjunction with the detailed description thereof and summary herein, the foregoing description is intended to illustrate and not limit the scope of the disclosure, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the claims. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims.

[0113] Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein. As used throughout the specification and claims, “a” and / or “an” may refer to one or more than one. Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, percent, ratio, reaction conditions, and so forth used in the specification are to be understood as being modified in all instances by the term “about,” whether or not the term “about” is present. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification are approximations that may vary depending upon the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0114] It is to be understood that each component, compound, substituent or parameter disclosed herein is to be interpreted as being disclosed for use alone or in combination with one or more of each and every other component, compound, substituent or parameter disclosed herein.

[0115] It is further understood that each range disclosed herein is to be interpreted as a disclosure of each specific value within the disclosed range that has the same number of significant digits. Thus, a range of from 1 to 4 is to be interpreted as an express disclosure of the values 1, 2, 3 and 4 as well as any range of such values such as 1 to 4, 1 to 3, 1 to 2, 2 to 4, 2 to 3 and so forth.

[0116] It is further understood that each lower limit of each range disclosed herein is to be interpreted as disclosed in combination with each upper limit of each range and each specific value within each range disclosed herein for the same component, compounds, substituent or parameter. Thus, this disclosure to be interpreted as a disclosure of all ranges derived by combining each lower limit of each range with each upper limit of each range or with each specific value within each range, or by combining each upper limit of each range with each specific value within each range.

[0117] Furthermore, specific amounts / values of a component, compound, substituent or parameter disclosed in the description or an example is to be interpreted as a disclosure of either a lower or an upper limit of a range and thus can be combined with any other lower or upper limit of a range or specific amount / value for the same component, compound, substituent or parameter disclosed elsewhere in the application to form a range for that component, compound, substituent or parameter.

Examples

example 1

[0105]This Examples evaluated stochastic pre-ignition (SPI) per 1000 cycles using hydrogen-fueled internal combustion engines at the Graz University of Technology (Austria). SPI was evaluated using a test method developed at the Graz University of Technology using a 4 cylinder 2.0 liter turbocharged and direct-injection passenger car engine converted to run on hydrogen fuel. The engine had a compression ratio of 9.8 and the turbocharger utilized variable turbine geometry.

[0106]The evaluation of SPI involved dosing a small defined quantity of the lubricant (e.g., about 0.6 grams per kilowatt-hours) was introduced as aerosolized drops into the intake area of one individual cylinder using an external dosing system and a dosing lance. The result for each test lubricant was derived from the number of pre-ignition events at the relevant cylinder during the dosing phase, while the other cylinders act as statistical reference.

[0107]The oil dosing was carried out at a steady-state operating ...

Claims

1. A lubricating oil composition configured for lubricating an internal combustion engine fueled with a fuel having an auto-ignition temperature greater than about 700K, the lubricating oil composition comprising:one or more base oils of lubricating viscosity; anda viscosity modifier olefin copolymer having a weight average molecular weight of about 200,000 to about 500,000 g / mol, about 55 mol percent or less of ethylene monomer content, and a shear stability index as measured pursuant to ASTM D6278 of 50 to 55.

2. The lubricating oil composition of claim 1, wherein the one or more base oils of lubricating viscosity includes one or more API Group I base oils, one or more API Group II base oils, one or more API Group III base oils, or combinations thereof.

3. The lubricating oil composition of claim 2, wherein lubricating oil composition further includes an overbased magnesium-containing metal detergent having a TBN of at least about 200 (ASTM D2896) and providing about 1000 to about 3000 ppm of magnesium to the lubricating oil composition.

4. The lubricating oil composition of claim 1, wherein the viscosity modifier olefin copolymer includes about 45 to about 55 mol percent of ethylene monomer content and about 45 to about 55 mol percent of propylene monomer content.

5. The lubricating oil composition of claim 4, wherein the wherein the lubricating oil composition includes about 0.6 weight percent to about 2 weight percent, based on active copolymer content, of the viscosity modifier olefin copolymer.

6. The lubricating oil composition of claim 5, wherein the viscosity modifier olefin copolymer is diluted in an API Group I and / or Group II base oil, and wherein the olefin copolymer is about 5 to about 15 weight percent of active copolymer content in the API Group I or Group II base oil.

7. The lubricating oil composition of claim 1, wherein the lubricating oil composition is substantially free of poly(meth)acrylate copolymers.

8. The lubricating oil composition of claim 1, wherein the fuel having an auto-ignition temperature greater than about 700K is hydrogen fuel.

9. The lubricating oil composition of claim 1, wherein the lubricating oil composition has an average measured stochastic pre-ignition (SPI) of about 50 SPI counts or less per 1000 cycles at 1350 rpm and 17 bar brake mean effective pressure (BMEP).

10. A method of lubricating an internal combustion engine when fueled with a fuel having an auto-ignition temperature greater than about 700K to mitigate abnormal combustion events, the method comprising:lubricating a crankcase of an internal combustion engine with a lubricating oil composition and combusting a fuel having an auto-ignition temperature greater than about 700K in the internal combustion engine; andwherein the lubricating oil composition includes a composition of claim 1.

11. The method of claim 10, wherein the one or more base oils of lubricating viscosity includes one or more API Group I base oils, one or more API Group II base oils, one or more API Group III base oils, or combinations thereof.

12. The method of claim 11, wherein lubricating oil composition further includes an overbased magnesium-containing metal detergent having a TBN of at least about 200 (ASTM D2896) and providing about 1000 to about 3000 ppm of magnesium to the lubricating oil composition.

13. The method of claim 10, wherein the viscosity modifier olefin copolymer includes about 45 to about 55 mol percent of ethylene monomer content and about 45 to about 55 mol percent of propylene monomer content.

14. The method of claim 13, wherein the wherein the lubricating oil composition includes about 0.6 weight percent to about 2 weight percent, based on active copolymer content, of the viscosity modifier olefin copolymer.

15. The method of claim 14, wherein the viscosity modifier olefin copolymer is diluted in an API Group I and / or Group II base oil, and wherein the olefin copolymer is about 5 to about 15 weight percent of active copolymer content in the API Group I or Group II base oil.

16. The method of claim 10, wherein the lubricating oil composition is substantially free of poly(meth)acrylate copolymers.

17. The method of claim 10, wherein the fuel having an auto-ignition temperature greater than about 700K is hydrogen fuel.

18. The method of claim 10, wherein the lubricating oil composition has an average measured stochastic pre-ignition (SPI) of about 50 SPI counts or less per 1000 cycles at 1350 rpm and 17 bar brake mean effective pressure (BMEP).

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